Afghanistan
The Islamic Republic of Iran
Iraq
Jordan
Lebanon
Pakistan
The Syrian Arab Republic
Turkey
S. H. Hussaini
INTRODUCTION
Afghanistan has a land area of 63 million ha. It has a total population of 18.8 million and 85 percent of the population is engaged in agriculture. The country is bordered by Tajikistan, Uzbekistan, and Turkmenistan on the north, Pakistan on the south, China on the east and Iran on the west. Wheat is the staple food. Before 1979, the total per caput consumption of wheat in Afghanistan was one of the highest in the world (180 kg per year) and provided nearly 80 percent of the annual caloric intake. Barley is a minor food crop in Afghanistan and accounts for only 5 percent of total animal fodder.
About 12 percent (7.6 million ha) of the total land area in Afghanistan is arable and 87 percent of the total cultivated land is under cereal production. Wheat is the most important crop and is grown on 57 percent of the land used for cereal production. Most Afghan farmers use local cultivars. Recently introduced varieties include Sonalika, Pak-81 and Pir Sabak-85. Two other varieties, ICW-1471 and GIRK, are currently being screened at Mazar-i-Sharif. The commonly grown varieties include Darul-Aman-1, Darul-Aman-4, T-Mutant, Bizostaya, and Nicozari (FAO, 1993).Yield estimates in 1991/92 showed an average yield of 2 500 kg per hectare using improved varieties and 1 050 kg per hectare using local cultivars. Most of the wheat is produced under irrigation (SCA, 1991). Rain-fed or dryland wheat production is an important practice in northern Afghanistan, but yields can be as low as 800 kg per hectare.
Wheat is grown over a large altitudinal range from the 300-m lower steppes to over 3 500 m. Seeding is accomplished either in autumn as an early planting or in spring as a late planting. In the mid-1970s, the country imported about 120 000 tonnes of wheat per year. Current figures are not available as a result of the war. Wheat is imported by both the Government and international agencies as well as by private merchants from the former Union of Soviet Socialist Republics, Iran and Pakistan.
If Afghanistan is to attain wheat self-sufficiency, concerted efforts will be required to reduce crop losses caused by insect pests and diseases. For example, the Swedish Committee for Afghanistan (SCA), an international non-governmental organization (NGO), estimated that annual losses from insect pests and diseases averaged 77 952 tonnes for the ten northern provinces (SCA, 1989).
The most important diseases of wheat are the rusts and smuts. These occur commonly in all wheat-growing areas in Afghanistan. The most important insect pests are Moroccan locusts and sunn pest. The sunn pest complex is represented by a number of genera, such as Eurygaster (Donskoff, 1966; Remaudière, 1959; Remaudière, 1961), Dolycoris, Aelia, Carpocoris and Eurydema (Harvey, 1990).
During the 1989/90 growing season, sunn pest caused serious damage to wheat in the northern provinces of Badghis, Faryab, Jawzjan, Saripul and Mazar. The severe damage caused to the wheat crop served as an alarm to the United Nations (UN) in its efforts to meet the food requirements of rural Afghans and returning refugees. In 1990, the FAO Sunn Pest/Locust Control Project was established with headquarters in Mazar-i-Sharif in northern Afghanistan, using funds from the UN Office for Coordination of Humanitarian Assistance to Afghanistan. In three successive campaign years, the FAO Sunn Pest/Locust Control Project has supplied ultra-low-volume sprayers (micro-ULV) and chemicals, and has provided training to rural Afghans in pesticide application, safety and handling techniques. Trained personnel are maintained by the project and are used for further training of farmers in local communities.
Currently, there are few active government policies regarding the production of wheat. It has been government policy to distribute improved wheat seed and to provide inorganic fertilizer to wheat growers. Tractors and other farm machinery were also hired or loaned to large-scale producers. These programmes have been less active since the onset of the war and the once-large irrigation systems have been mostly destroyed or have fallen into disrepair.
The Government now relies entirely on the United Nations and its collaborating NGOs for the screening and distribution of improved wheat seed and agricultural chemicals to enhance wheat production in the country.
THE SUNN PEST PROBLEM IN AFGHANISTAN
Sunn pest, or kafshak as it is known locally, was first reported in the northern province of Faryab in the 1950s. Some 20 years later the pest was observed in wheat fields in the western province of Herat. It is believed that the insect migrated to Afghanistan from Iran or from the central Asian countries of Turkmenistan or Uzbekistan. Although population densities vary from one province to another, the sunn pest is now found throughout northern Afghanistan. Sunn pest was considered economically unimportant until 1989 when large populations of the pest attacked and destroyed wheat fields in the north. In that year, some wheat farmers in the provinces of Faryab and Badghis suffered 100 percent crop losses.
Sunn pest has become one of the most important insect pests of wheat in the ten northern provinces (Herat, Badghis, Faryab, Jawzjan, Saripul, Balkh, Samangan, Baghlan, Kunduz and Takhar), irrespective of altitude.
Two species of sunn pest, Eurygaster integriceps and Aelia rostrata, are thought to occur in northern Afghanistan. In 1962, samples collected by the Department of Agriculture in Miamana in northern Afghanistan showed the presence of only E. integriceps (Brown and Eralp, 1962). In 1990, an entomologist and FAO consultant, Dr Harvey (Harvey, 1990), collected samples of the pest from infested wheat fields in Faryab province for identification at the Commonwealth Agricultural Bureaux (CAB) International Institute of Entomology (HE) in the United Kingdom. E. integriceps, which is known to be common in the area, was not found among the samples identified. Instead, four other pentatomids, Dolycoris penicillatus Horvath, Aelia melanota Fieber, Carpocoris coreamus Distant and Eurydema sp., were identified. The most common species was D. penicillatus. Since E. integriceps was not identified among the samples collected, it is conceivable that more than one species of sunn pest causes economic damage to wheat in Afghanistan. The local people also tend to believe that more than one form of the insect exist in the area, although this may be attributed to colour variations within individual species.
ECONOMIC IMPACT AND YIELD LOSSES
The 1989 SCA survey indicated that sunn pest inflicts damage on wheat crops from late May to early June. Over 60 percent of spring wheat fields were either infested or exhibited signs of an earlier infestation. Hand-threshing inspections of these previously infested fields revealed that grain development had been reduced by as much as 75 to 100 percent.
In wheat fields planted earlier, grain development was reduced by 25 to 30 percent. The crop losses attributable largely to sunn pest would have caused food deficits affecting approximately 350 000 people (SCA, 1989). There are no statistical data on wheat or barley losses caused exclusively by sunn pest in Afghanistan. Figures presented generally account for a combination of insects and other factors (Table 16).
AREA INFESTED BY SUNN PEST OVER THE PAST 20 YEARS
Sunn pest was first reported in the northern province of Faryab in 1950 (Baquee and Jacon, 1989). During the 1970s, the insect spread westwards to Herat and Badghis and eastwards to Saripul, Jawzjan, Balkh and Samangan.
Survey reports from SCA (1989) showed that 0.5 million ha of cropland had been infested by a combination of locusts and sunn pests. This figure must be considered a minimum since the surveyors were able to visit only a small part of each province.
VARIETAL SENSITIVITY TO SUNN PEST
The 1989 infestation was particularly serious because all of the cereal varieties in use were highly susceptible. Sunn pest caused the greatest amount of damage to immature crops of late-maturing local wheat varieties.
CONTROL MEASURES
It was not until the establishment of the FAO Sunn Pest/Locust Control Project at Mazar-i-Sharif in 1990 that a coordinated programme was developed against sunn pest. In that year, the project issued backpack sprayers and large amounts of pesticides to farmers. The use of conventional high-volume applicators, however, proved very difficult since farmers needed to transport large quantities of water to their wheat fields in the mountains. This was particularly difficult in the north where water was a limiting factor. As a consequence, the FAO Sunn Pest/Locust Control Project introduced the use of ULV applicators.
TABLE 16 - Provincial crop loss caused by locust/sunn pest
|
Province |
Population |
Wheat production lost to insects |
Wheat deficit |
|
Herat |
341 000 |
25 175 |
100 411 |
|
Badghis |
360 000 |
3 429 |
11 781 |
|
Faryab |
506 000 |
2 261 |
11 851 |
|
Jawzjan |
344 000 |
5 005 |
13 833 |
|
Balkh |
302 000 |
8 771 |
NA |
|
Samangan |
446 000 |
13 736 |
64 361 |
|
Baghlan |
523 000 |
10 172 |
NA |
|
Kunduz |
352 000 |
4 212 |
NA |
|
Takhar |
392 000 |
922 |
NA |
|
Badakhshan |
471 000 |
4 269 |
22 762 |
NA = data not available.
Source: SCA, 1989.
The project trained 90 crop extensionists from seven provinces as trainers in appropriate pest control techniques. These trainers then trained a total of 1 800 farmers prior to the 1991 cropping season. ULV sprayers and a specified amount of pesticide were issued to each trained person for appropriate field use. The training exercise has become an annual programme and over 4 000 farmers have benefited to date. Similar collaborative efforts have been initiated with the national plant protection services. The programme has been campaign-based and, therefore, dependent solely on pesticides. There has been little time to consider biological control methods. Some farmers do resort to other methods of control where pesticides are not readily available.
Mechanical control has been properly used in the districts of Almar and Qaysar in Faryab where the farming population was mobilized to hand pick the pest in the summer of 1990. Farmers were compensated Af.4 000 (then equivalent to US$8) for every 7 kg of insects collected and taken to the local commanders. Large numbers of insects were collected, but the programme was abandoned because local authorities concluded that no amount of hand gathering would have a significant impact on the size of sunn pest populations.
The Plant Protection and Quarantine Department (PPQD) also launched a campaign against sunn pest by burning bushes at overwintering sites. This practice was also discontinued as the bush fires were not controlled and usually ended up burning animal grazing lands.
Crop varieties grown are generally low-yielding and highly susceptible. Since the late-planted wheat fields suffered more from sunn pest damage than the early-planted crop during the 1990 pest outbreaks, it may be feasible to use an early variety which will mature before the insects emerge from hibernation. Few improved wheat varieties have been introduced in recent years. One of the new introductions, Sonalika, is high-yielding and early-maturing. It is hoped that the early-maturing trait in this variety may be useful as a means of preventing or reducing sunn pest damage. Field trials are under way to investigate the effects of variations in planting dates on the ability of Sonalika to avoid sunn pest attack.
The FAO Sunn Pest/Locust Control Project has successfully operated a chemical control programme in the ten northern provinces (sunn pest endemic region) either through direct project involvement or through some of the Pakistan-based NGOs engaged in plant protection in Afghanistan. Farmers in these northern provinces have been trained in appropriate pesticide application techniques using ULV applicators. There has been considerable reduction in pest infestation levels, and hence crop losses, of sunn pest and locusts. Unfortunately, field conditions in Afghanistan have limited the possibilities for field studies on environmental and other factors affecting, or affected by, pesticide use. To date, very few pesticide poisoning cases have been reported, and most of these have involved farm animals.
The role of PPQD in these circumstances is to offer training in government-controlled areas and to facilitate the distribution of inputs. During the 1990-92 campaign, PPQD was restricted to limited areas controlled by the Government as a result of hazards that government officials faced while working in areas controlled by the opposition.
RESEARCH PROGRAMMES
There has been little research on sunn pest at local plant protection and quarantine stations. Most researchers left the country during the 14 years of war and the few who remained do not have proper facilities. The FAO Sunn Pest/Locust Control Project is the only reliable programme for the control of the insect in Afghanistan today. The project is not research oriented, but through another FAO programme it has distributed improved wheat seed to farmers. Multisite trial plots have been established at various plant protection stations in the north. Those involved in the project hope to investigate planting dates, pest biology and other environmental factors affecting the control of sunn pest in the area.
CONCLUSIONS
In spite of unpredictable field security situations, the FAO project has successfully trained and engaged 100 crop extensionists and supervisor trainers and over 50 extensionists at various provincial plant protection stations throughout the northern portion of the country. To date, over 4 000 have been trained farmers in pesticide application techniques. Field information indicates that over 5 000 farmers benefited directly from the programme and a total of 240 000 ha was treated against sunn pest and locusts from 1990 to 1992.
RECOMMENDATIONS
The ULV pesticide application programme has been successful in reaching the intended target communities, but its reliance on chemical control may eventually draw the farmers into a "pesticide treadmill" unless alternatives are sought.
In the short term (two years), the FAO programme aims to increase the introduction of alternatives to chemical control using results of the current trials examining the advantages of early-maturing seed and by emphasizing district-level community plant protection education. Chemicals will no longer be distributed freely and will have to be purchased at cost through trained and certified community crop extensionists.
Short regional training courses need to be organized for provincial PPQD staff and community crop extensionists. These courses could take place in Pakistan, Iran, Turkey or Uzbekistan.
For the longer-term management of sunn pest populations below economic injury levels, it will be necessary to restructure and improve the plant protection capabilities of PPQD, especially regarding its roles as trainers and technical advisers. This should include providing research facilities and developing a regional network whereby Afghan scientists can establish close contact with colleagues in the subregion. Since Afghanistan has been politically isolated from other countries within the region, scientists need to attend workshops, seminars and training courses in other countries.
REFERENCES
Baquee, A. & Jacon, J. 1989. A preliminary report, Badghis insect infestation survey. 1 August 1989. Peshawar, Pakistan.
Brown, E.S. & Eralp, P. 1962. The distribution of species of Eurygaster Lap. (Hemiptera: Scutelleridae) in Middle Eastern countries. Ann. Mag. Nat. Hist., 13: 65-81.
Donskoff, M. 1966. Sunn pest control. Report to the Government of Afghanistan. FAO/UNDP Report No. 2190. 10 pp.
FAO. 1993. Seed production and training. FAO Project AFG/86/010. Mazar, Afghanistan, FAO.
Harvey, A.W. 1990. Outbreak of sunn pest in Afghanistan. Rome, FAO. (Unpublished report)
Lal, B.S. 1973. Plant diseases in Afghanistan. Indian Technical and Economic Cooperation (ITEC) Programme. 2nd ed. p. 4-6.
Remaudière, G. 1959. Sunn pest in the Near East and Mediterranean countries. Report to the Governments of Afghanistan, Iran, Lebanon, Turkey and the United Arab Republic. FAO/EPTA Report No. 1225. 16 pp.
Remaudière, G. 1961. Afghanistan, Iran, Lebanon and the United Arab Republic: sunn pest investigations in 1960. Report to the Governments. FAO/EPTA Report No. 1392. 21 pp.
SCA. 1989. Locust and sunn pest affected districts of Afghanistan. SCA/06/ 220889. p. 1-10. Peshawar, Pakistan, Swedish Committee for Afghanistan.
SCA. 1991. Report on Northern Afghanistan crop protection project. AFG/90/007, ARD/RAS/SCA 0-1-02. p. 1-16, Swedish Committee for Afghanistan.
A. Rassipour, G. Radjabi and M. Esmaili
INTRODUCTION
The areas cultivated with wheat and barley in Iran are 6.5 million ha and 2.5 million ha, respectively. Varieties used include Ghods, Azadi, Eenea, Bezostaya, Falat, Khazar, Arvand, Roashan, Tabassi, Bayat, Moghan and Navid. Production for irrigated wheat is around 2 900 kg per hectare, while rain-fed wheat production averages 800 kg per hectare. Irrigated and rain-fed barley yield approximately the same as irrigated and rain-fed wheat. No wheat or barley are exported, while 2 460 000 tonnes of wheat were imported in 1992. There were no barley imports.
The major insect pest problems are: Eurygaster integriceps Put., Aelia furcula. Fieb., Dolycoris penicillatus Hor., Zabrus tenebrioides Hrbat., Anisoolia austriaca Hrbat., Anisoplia leucaspis Cast., Oulema melanopus L., Apamea sordens Hfn., Syringopais temperatella Lad., Cephus pygmaeus L., Chlorops pumilionis Bjerk., Domomyza ambigua Fall., Haplothrips tritici Kurdj., Schizaphis graminum Rond., Diuraphis noxia Mord., Sitobion avenae Fab., Metopolophium dirhodum Walker, Sipha maydis Pass. and Porphyrophora tritici Bod.
Other pests of wheat and barley include nematodes, rats and birds. Cereal diseases include rusts, smuts, powdery mildews, septoria and fusarium.
Yield losses caused by insects, diseases and weeds would range up to 70 percent if sprays were not used. Monetary losses vary from year to year.
GOVERNMENT POLICY ON WHEAT AND BARLEY PRODUCTION
Particularly in recent years, government policy has been based on supporting farmers by providing them with financial aid and improved seeds. In addition, the Government provides fertilizers and pesticides free to the farmer. It also guarantees purchase of the crop and insures yields against loss. The Ministry of Agriculture is currently trying to persuade farmers to increase the average yield per hectare through a Wheat Extension Project (WEP).
HISTORY OF THE SUNN PEST PROBLEM
The earliest record of sunn pest in Iran dates from about 1862 (Farsnameh Nasseri), when a severe sunn pest outbreak caused panic in Fars province. There is little doubt that the harmful activity of sunn pest goes back even further into Iran's history, with outbreaks occurring whenever conditions were favourable. The first chemical treatment was performed about 40 years ago.
GEOGRAPHICAL DISTRIBUTION
At present, Eurygaster integriceps, the most destructive species, is found wherever wheat is grown. The main infestation areas are in the provinces of Teheran, Markaz, Esfahan, Fars, Bakhtaran, Kurdistan, Lorestan, Zanjan, Ealam and Khorasan. Sunn pest is absent from narrow strips along the Oman Sea, the Arabian Gulf and the Caspian Sea. E. maura L. is distributed mainly in the Caspian Sea region and around Marand and Mäku. E. testudinaria Geoff. is a recently identified species from Mazan Deran. Aelia furcula is found in the western, central and northeastern parts of the country. A. melanota Fieb. is found in some central, western and southern areas of Iran, as is A. virgata Klug. A. rostrata Boh. is found at low densities in some parts of the country. Dolycoris pennicillatus is distributed mainly in eastern, northeastern, central and southwestern Iran, while Carpocoris fuscispinus Boh. is found at low densities almost everywhere.
ECONOMIC IMPACT AND YIELD LOSSES
E. integriceps currently infests about 1 million ha of wheat and barley. The average yield losses are estimated at 20 to 30 percent if the insects are not controlled. There has been a nearly tenfold increase in the infested area over the last 20 years.
AREA INFESTED BY SUNN PEST OVER THE PAST 20 YEARS
Table 17 shows the gradual increase of the total area treated against sunn pest.
TABLE 17 - Total area in Iran treated with chemical insecticides against sunn pest
|
Year |
Area |
|
1976 |
75 153 |
|
1977 |
107 577 |
|
1978 |
93 744 |
|
1979 |
53 263 |
|
1980 |
81 566 |
|
1981 |
112 506 |
|
1982 |
202 532 |
|
1983 |
273 357 |
|
1984 |
469 442 |
|
1985 |
521 981 |
|
1986 |
478 345 |
|
1987 |
837 358 |
|
1988 |
933 994 |
|
1989 |
928 919 |
|
1990 |
811 195 |
|
1991 |
927 366 |
|
1992 |
991 035 |
VARIETAL SENSITIVITY TO SUNN PEST
Preliminary investigations reveal that there are differences in plant response to sunn pest among the wheat varieties cultivated in Iran.
CONTROL MEASURES
The only chemical compound now used to control sunn pest is fenitrothion 50% applied as an emulsifiable concentrate at a rate of 1.2 litres per hectare.
At present there are no biological control efforts against sunn pest in Iran. Research is currently being conducted on cultural control methods such as the use of resistant varieties, the practice of double-harvesting and the value of varying sowing dates. Of particular interest are double-harvesting and the effectiveness of early and rapid harvesting. In conjunction with these techniques, attempts are being made to convince farmers of their advantages.
In areas with pest populations above the economic level, fenitrothion is used exclusively as a sunn pest spray. A network of forecasting stations estimates the specific areas to be sprayed. Forecasting is based on regular sampling in aestivation and hibernation sites as well as in cereal fields in early spring.
In conducting chemical control against sunn pest, other insect pests such as aphids and thrips are also killed. Some beneficial arthropods are also killed inadvertently.
The Plant Protection Organization is responsible for sunn pest control in Iran with recommendations made by the Plant Pests and Diseases Research Institute of the Ministry of Agriculture.
The cost for spraying is estimated at about 5 000 rials per hectare. This figure does not include research expenses, sampling, forecasting and postspraying impact analyses, however.
RESEARCH PROGRAMMES
Many studies have been conducted in Iran, several of which are not yet concluded. The major research areas under investigation include:
· the life cycle of sunn pest in different regions of Iran;· identification and evaluation of natural enemies of sunn pest;
· mass-production of sunn pest egg parasitoids;
· estimation of the effectiveness of laboratory-reared egg parasitoids under a wide range of field conditions;
· behaviour of egg parasitoids in the laboratory;
· dipterous parasitoids of sunn pest and their distribution, life cycle and effectiveness;
· estimation of the effectiveness of different chemical compounds on adults and nymphs;
· economic thresholds for adults and nymphs;
· preference of sunn pest for different cereal varieties;
· degradation of rangeland and its connection with the gradual and steady expansion of sunn pest, particularly in rain-fed areas;
· early and rapid harvesting of wheat to prevent the insect from accumulating sufficient fat reserves. This is considered a fundamental measure in reducing sunn pest populations;
· factors affecting the relationship between sunn pest and winter wheat;
· factors causing cyclic behaviour of sunn pest populations in irrigated wheat in Esfahan.
REGIONAL AND INTERREGIONAL COOPERATION
Sunn pest investigations in Iran were begun by Russian experts in cooperation with Iranian entomologists. Two Turkish entomologists spent three months in Iran working in laboratories on the mass-production of sunn pest and its hymenopterous parasitoids.
FAO, the Sunn Pest Information and Documentation Centre of the Pasteur Institute in Paris and CENTO have played the greatest role in inter-regional cooperation. Their cooperation dealt mainly with biological control and bioecology. FAO and CENTO have been the only external supporters of sunn pest activities in Iran.
ACHIEVEMENTS
Some research projects, particularly those undertaken in recent years, have been successful. One of the major discoveries arising from research is that reliance on chemical control measures alone cannot resolve the sunn pest problem and additional means of managing the pest are needed.
CONCLUSIONS
The basic cause of the expansion of sunn pest-infested areas over the last two decades may be the degradation of rangelands throughout Iran. Deterioration has resulted from the imposition of wheat cultivation on rangelands that are unsuitable for cultivation and from excessive grazing. The rate of degradation will ultimately prove catastrophic. Some 30 species, subspecies and varieties of wild plants belonging to the families Gramineae, Compositea, Caryophyllaceae and Papsveracea have been found as sunn pest hosts and as hibernation refuges at higher altitudes.
Parasitized eggs of sunn pest have also been found at higher altitudes. Egg parasitoids include Trissolcus grandis Thomson, T. semistriatus Nees, T. basalis Wollaston and T. rufiventris Mayr. They are frequently found in mountainous areas where vegetation is abundant.
Food quality affects the ability of the sunn pest to migrate to mountain hibernation sites and to survive the winter. Cyclic, six- to eight-year population explosions of sunn pest in permanently infested areas of Esfahan prior to the use of chemical insecticides, probably resulted from changes in food supply and quality. These observations led to giving serious consideration to early and rapid harvesting which might deprive the sunn pest of accumulated food reserves. Disruption of body fat accumulation might reduce the immediate sunn pest population as well as having a negative impact on future generations. Females from subsequent generations possessing fewer food reserves would in turn be more vulnerable to early and rapid harvesting.
RECOMMENDATIONS
The ongoing studies on cultural methods, natural enemies and resistant varieties should be intensified.
More emphasis should be placed on regional and inter-regional cooperation.
Visits by researchers and pest control managers should be made to the infested countries of the region to obtain a broader perspective on the insect under different circumstances.
Q.K. Zuwain and A. Al-Khafaji
INTRODUCTION
Iraq is an agricultural country with about 12 million ha of arable land, but with only 5.8 million ha currently in use for agriculture. Approximately 81.5 percent of the total area in production is devoted to producing wheat, barley, rice and maize, in that order. The remaining 18.5 percent is planted with a wide variety of crops, the most important being date-palm, citrus fruits, vegetables, tobacco, grapes, sugar cane and stone fruits.
Iraq is divided into three geographical regions. The northern region, with intermediate and high altitudes, has high rainfall, cold, snowy winters and dry, cool summers. In the central region, the winter is cool and rainy while the summer is long, dry and very hot. The winter in southern Iraq is cool with low rainfall, while summer is very hot and humid. The altitude is low in the south, and 50 percent of the land is covered by water.
Humans first planted wheat in ancient Mesopotamia, where archaeological research has revealed the different farming practices employed in ancient times. Today, wheat and barley are grown in different regions of Iraq, and irrigation systems vary from region to region. Rain-fed wheat and barley production is located primarily in the north where cultivated areas may be classified into three categories according to the regularity of rainfall: areas with regular rainfall; areas with semiregular rainfall; and areas without regular rainfall. Agriculture in the central and southern regions is dependent on irrigation.
Total area and production of wheat and barley over the period 1986 to 1991 are shown in Table 18.
Several cultivars of wheat and barley are grown in Iraq. The most important soft wheat cultivars are Mexipak, Abu-Ghraib-3, Inia-66, Nouri-70, Aras and Saber-Be. The hard wheat cultivars are Cockret C-71, Gerardo-575, Bakra-Ju and Santor-Capelli.
TABLE 18 - Area and production of wheat and barley under different irrigation systems in Iraq
|
Irrigation system |
Area (ha) |
Production |
Yield |
||
|
Harvested |
Cultivated |
('000 tonnes) |
(kg/ha) |
||
|
Wheat Irrigated |
2356.6 |
2955.3 |
261.6 |
71.0 |
61.6 |
|
Rain-fed |
8876.1 |
10630.3 |
713.5 |
50.1 |
42.4 |
|
Total |
11232.7 |
13585.6 |
975.1 |
54.4 |
41.8 |
|
Barley Irrigated |
4796.2 |
6123.6 |
446.4 |
57.8 |
47.1 |
|
Rain-fed |
8352.6 |
11314.8 |
638.9 |
44.8 |
36.4 |
|
Total |
13148.8 |
17438.4 |
1 085.3 |
50.6 |
40.4 |
The main six-row barley cultivars are Arevat, Nomar, Jazira-120, C.M.-67 and California-mariot, while two-row cultivars are Cleaber and a local black barley.
Iraq imported 2.3 million tonnes of wheat and 386 000 tonnes of barley in 1989, and exported 40 000 tonnes of barley.
Productivity levels of all important crops in Iraq are low compared with developed countries. As a result, the Iraqi Government has implemented several measures to improve these crops quantitatively and qualitatively. Measures include introducing mechanization, fertilizers and pest management and recommending specific varieties. Priority has also been given to expanding the area planted to new and improved cultivars.
The major insects and diseases attacking wheat and barley in Iraq are as follows.
Insects: sunn pest (Eurygaster integriceps Put.) causes severe damage to wheat and barley and is found in the most important wheat-producing areas of Iraq. It is Iraq's most important insect pest of wheat and barley. Less important cereal pests include Dolycoris baccarum L., Aelia acuminata L., Syringopais temperatella Led., Carpocoris podicus, Cephus pygmaeus L., Oria musculosa Hubn., Exaeretopus tritici Williams and Zabrus mono Menetries.
Plant diseases on wheat: covered smut, Tilletia foetida; stem rust, Puccinia graminis tritici; and ergot, Clavicepts jourpura.
Plant diseases on barley: loose smut, Ustilago hordei and black stem rust, Puccinia graminis hordei.
The ear cockle nematode, Anguinis tritici, is found on both wheat and barley.
There are no exact data on crop losses caused by these pests on either wheat or barley.
THE SUNN PEST PROBLEM
Although Iraq is considered a homeland of wheat and barley, the first reports of sunn pest in Iraq were made during the 1920s by J.F. Webster and A. Dutt in northern Iraq. During the 1930s and 1940s, several Iraqi entomologists, such as Alber Memerian and Dhiaa Ahmed, studied the distribution and damage attributed to sunn pest. In the 1950s, other Iraqi scientists such as Haider Al-Haidari and Authman Ridha Ali, studied sunn pest biology, ecology and its chemical and biological control. From 1957 to 1960, E.S. Bron conducted intensive studies on the sunn pest in Iraq, Iran, Turkey and Pakistan. In particular, he examined the economic importance of the insect and biotic and abiotic factors affecting its life history. During this period, other foreign experts, including Remaudière and Niazi Lodos, studied the biological control of sunn pest.
Several forms of chemical insecticide control have been used since the 1920s. Particularly important has been the aerial application of insecticides.
From 1960 to 1968, sunn pest populations decreased to insignificant levels in the Near East. In 1968, however, the pest reappeared in outbreaks in Iran and Turkey, but not in Iraq.
In 1972, the Iraqi Government issued Law No. 4, which identified the sunn pest as an important cereal pest. Since then its control has been completely funded by the Government.
Observations by experts in 1984 indicated that sunn pest was present in wheat and barley fields, but did not cause significant damage to the crops. However, by 1987, the outbreak was severe and the Iraqi Government sprayed about 50 000 ha. Subsequently, insecticide applications increased annually until they covered 300 000 ha in 1992. More than 400 000 ha were expected to be sprayed against sunn pest in 1993.
GEOGRAPHICAL DISTRIBUTION OF SUNN PEST
All previous references, including surveys, indicate that the distribution of sunn pest in Iraq is bounded on the south by the Himreen mountains, on the north by the Turkish border, on the east and northeast by Iran and on the west by the Sinjar mountains. Sunn pest populations are highest in northern Iraq in a region around 36 to 37.3° north latitude and 42.3 to 44.2° east longitude. These areas lie within Nineveh, Duhok, Sulaimaniya and Arbil provinces. Although sunn pest has been found in fields of the central provinces, such as Salah Al-Din, Diyala, Anbar and Baghdad, populations have been low and have caused little damage. Sunn pest has not been found in southern Iraq.
ECONOMIC IMPACT AND YIELD LOSSES
In Iraq, sunn pest causes between 20 and 30 percent yield loss in barley and between 70 and 90 percent in wheat. Damage varies according to population density and the timing of infestation.
VARIETAL SENSITIVITY TO SUNN PEST
All wheat and barley cultivars tested against sunn pest in Iraq have been found to be susceptible, although early sowing and harvesting may enable the plant to escape damage.
CONTROL MEASURES
Chemical control. Chemical control is currently the only method used to control sunn pest in Iraq and has proved effective. Aircraft are used to spray vast areas of infested fields. Sumithion S -100 is recommended and is applied at a rate of 2 litres per hectare.
Biological control. No formal biological studies have been conducted on sunn pest because of the low population densities recorded during the 1960s and 1970s, Sunn pest has recently become important, however, causing severe damage to both wheat and barley crops. Despite the lack of biological control studies, several enemies have been identified from wheat and barley fields in northern Iraq.
Predators of sunn pest in Iraq are: Chrysopa earned Steph., Colosoma maderae E, Diohabda fisheri Fald. and Cataglyphis bicolor F.
Parasitoids are: Trissolcus (Ascolcus) vassiilievi (Mayr.), T. grandis (Thaus.), T. semistriatus (Nees), T. rufiventris (Hymenoptera: Scelionidae), Phasia subcoleopterata L. (Diptera: Tachinidae, subfamily: Phasiinae), P. flaviventris Mg., Clytiomia heluola Mg., Gymnosoma desertorum Rohd., Helomyia ateratis Mg. and Cylindromyia brassicaria F.
AGRICULTURAL METHODS
At present, no agricultural methods (cultural control) are used in Iraq, although they may be used in the future.
CONTROL COSTS
The State Board of Plant Protection is officially in charge of chemical control of sunn pest in Iraq, with cooperation from entomologists in the Plant Protection Research Division (State Board of Agricultural Research). The spray programme depends on surveys to identify infestations and estimate the area infested prior to the occurrence of extensive damage. The decision to spray is made when an economic threshold is exceeded. The Iraqi Government covers all expenses for this programme.
The cost of controlling sunn pest in Iraq in 1991 was a little over US$20.25 million distributed as follows:
|
Aircraft rental |
US$ 4 500 000 |
|
Cost of chemicals |
5 250 000 |
|
Rental of sprayers and other equipment |
677 700 |
|
Rental of field cars and tankers |
135 000 |
|
Supervisors' wages and maintenance |
9 700 000 |
|
Total |
US$ 20 262 700 |
RESEARCH PROGRAMMES
The State Board of Agricultural Research, Plant Protection Research Centre, in cooperation with the Directorate-General of Plant Protection, organizes research programmes to develop control measures as follows:
· to evaluate the possibility of controlling sunn pest in overwintering sites during diapause;
· to determine the most effective spraying date;
· to develop the use of natural enemies;
· to identify resistant and early-maturing varieties.
Regional cooperation
Regional cooperation among adjacent countries infested with sunn pest will decrease sunn pest damage to wheat and barley. Sunn pest migrates twice, during the spring/summer and prior to winter. It overwinters away from cereal fields. Since the pest diapauses in mountains near international borders, coordination of control activities within an integrated pest management (IPM) framework is important. Financial assistance from various international organizations should be made available for collaboration involving research and control measures.
CONCLUSIONS
Sunn pest was first found in Iraq at the beginning of this century. Many Iraqi scientists cooperated with foreign experts in studying different aspects of sunn pest biology, impact and control.
Sunn pest was found mainly in northern Iraq, especially in areas with consistent rainfall. It was also found at low densities in irrigated areas.
From 1960 to the mid-1980s, sunn pest densities in Iraq and the world (according to Russian references) were low. Regional wars, increased wheat and barley cultivation and other disrupting elements may have contributed to population outbreaks during the last few decades.
Natural enemies, including predators, parasitoids, fungi and bacteria, should be considered in an integrated programme for sunn pest management.
RECOMMENDATIONS
FAO, the International Centre for Agricultural Research in the Dry Areas (ICARDA) and other international organizations should support the research programmes on sunn pest in Iraq because currently there are financial and technical problems.
Regional cooperation is necessary for the establishment of an IPM programme for sunn pest.
A personnel training programme is essential.
Further surveys are required with cooperation from regional and international organizations, to determine sunn pest distribution.
M.F. Khasawneh
INTRODUCTION
Wheat and barley are the main crops grown in the rain-fed areas of Jordan. These crops are also grown under irrigation in southern Jordan (Table 19). The varieties grown in Jordan differ from one area to another. Wheat varieties are Horani 27, Hawawi and F8 and barley varieties include Rum, Axad 175 and Axad 76. The productivity of these varieties varies from area to area depending on the average amount of rainfall (Table 20). Jordan is not self-sufficient in wheat and barley production and depends on imports to cover national needs (Table 21).
TABLE 19 - Area planted to wheat and barley in Jordan (ha)
|
|
1990 |
1991 |
1992 |
1993 |
|
Wheat |
- |
- |
- |
71100 |
|
Barley |
34440 |
22570 |
83630 |
55010 |
TABLE 20 - Average wheat and barley production in Jordan (kg/per hectare)
|
|
Rain-fed |
Irrigated |
|
Wheat |
99 |
350 |
|
Barley |
70 |
250 |
TABLE 21 - Tonnes of wheat and barley imported into Jordan
|
|
1990 |
1991 |
1992 |
|
Wheat |
610985 |
759400 |
553100 |
|
Barley |
209488 |
252920 |
293480 |
Wheat and barley were rarely attacked by important diseases such as rusts and smuts until sunn pest became a major problem. Even so, no studies have been conducted to assess pest dynamics or damage.
The Jordanian Government currently encourages wheat and barley production by various means, including the following:
· supplying farmers with treated seeds, which are free of pests, at low prices;· buying farmers' produce at subsidized prices, thereby encouraging the production of wheat and barley;
· two major control efforts against sunn pest have been conducted at no cost to farmers in 1991/92 in central and southern Jordan;
· the Ministry of Agriculture is prepared to counteract sunn pest outbreaks when and wherever they occur.
THE SUNN PEST PROBLEM
Sunn pest was well known to farmers in past years, although by different names. It was not previously considered to be very important because of its low levels and the insignificant crop damage it caused. To date, no studies have been carried out on sunn pest control or biology.
There have been sunn pest outbreaks over the last three years in central and southern Jordan (Madaba, Karak). Nearly all wheat and barley fields in these regions were heavily infested. Sunn pest in Jordan was identified as Eurygaster integriceps Put.
CONTROL MEASURES
The only control tactic used for sunn pest in Jordan is chemical spraying. No other control measures, such as biological control, have been undertaken because of a lack of adequate research support and interest in those years when sunn pest was present but was considered to be insignificant.
Volaton ULV 930, a pesticide containing propoxur and dioxim, applied at a rate of 0.5 litres per hectare, was the only pesticide used during the last two control programmes. It was applied as both an aerial and a ground spray. The total cost of sunn pest control during the control programme in 1992 was US$210 300 (Table 22).
The Plant Protection Department of the Ministry of Agriculture is in charge of pest detection and supervises control programmes. It is also responsible for planning and supplying the various agricultural directorates with the necessary control plans. The directorates are the executives for the control of sunn pest within the area of their jurisdiction.
TABLE 22 - Cost of sunn pest control in Jordan in 1993
|
Item |
Cost (US$) |
|
Pesticides |
150000 |
|
Aircraft |
28000 |
|
Fuel |
3300 |
|
Maintenance |
4200 |
|
Allowance |
2300 |
|
Transportation |
3200 |
|
Reporting |
3300 |
|
Personnel |
16000 |
|
Total |
210300 |
RESEARCH PROGRAMMES
No research has been undertaken on sunn pest despite the outbreaks experienced over the past three years.
CONCLUSIONS
Jordan has begun to address the sunn pest problem, although there is a lack of past and current research. Chemical control programmes have been instigated and the Government is ready to implement them if and when sunn pest becomes a problem in the future.
RECOMMENDATIONS
Research should be carried out on the biology and epidemiology of sunn pest in Jordan. More data are needed on the extent of crop losses during sunn pest outbreaks. Studies on the economic threshold for sunn pest are also necessary. Regional coordination projects with clear pest management policies applicable to Jordan and the region are perhaps the most important requirement.
E. Mechelany
INTRODUCTION
Eurygaster integriceps, commonly known as sunn pest, is widespread throughout the Mediterranean basin where it is a serious pest of wheat and barley. In Lebanon, it is found wherever wheat is cultivated in the coastal, middle and interior regions of the country. In the Beka'a valley, it is found from Bar Elias Torbol near Ryak to Baalbek, an area lying between the Lebanon and Anti-Lebanon mountains. When sunn pest attack is intense, damage to grain yield is comparable to that of locusts.
In Lebanon, more wheat is produced under irrigation than in the relatively arid rain-fed areas. Production may reach 7 tonnes per hectare under irrigation, while averaging only 1 to 2 tonnes per hectare under rain-fed conditions. The area cultivated with wheat during the past four years ranged from 15 000 to 20 000 ha. The main varieties cultivated in Lebanon include the soft wheats Serie 82, Hermon and Baalbek. Hard wheats cultivated in Lebanon are Stock and Sebou, while barley varieties are Litani and Rihane. Lebanon exports neither wheat nor barley, but annually imports 400 000 tonnes of wheat.
Most Lebanese wheat varieties are resistant to insects and diseases. The most important common diseases in Lebanon are yellow rust, Puccinia glumarum or P. striiformis. The most serious cereal insect pests are sunn pest, E. integriceps Put. and Aelia rostrata Boh.
THE SUNN PEST PROBLEM
The sunn pest is an extremely serious hemipteran because it affects the level of grain production as well as grain quality. The degree of damage is influenced by the severity of the winter season. Very cold winters apparently decrease the spread of sunn pest outbreaks in Lebanon. A favourable climate for sunn pest, such as high temperature and humidity, encourages outbreaks. Yield losses caused by sunn pest are difficult to determine, but damage has not been economically significant over the last few years.
The Lebanese Government's current policy is to encourage wheat production and provide assistance to farmers in order to ensure good production, including control of sunn pest outbreaks.
The sunn pest first appeared in Lebanon in 1924. During most seasons, it appears in the Beka'a valley at the onset of spring when temperatures reach 20 to 22°C. The insect arrives in the Beka'a valley from hibernation sites on the two surrounding mountain ranges, the Lebanon and the Anti-Lebanon. It reproduces in cereal fields in the valleys. Normally, sunn pest populations are higher in irrigated cereals than in rain-fed cereals. There are predatory hymenoptera attacking sunn pest in Lebanon, such as Asolcus (microphanurus) semistriatus Nees, but little is known about these.
Chemicals used in the past to control sunn pest outbreaks included trichlorfon (1 200 g per hectare), oxydemeton-methyl (1 400 g per hectare) and parathion (1 400 g per hectare). Insecticide resistance to one or more of these chemicals has been observed. Trichlorfon generally gave 85 percent control, oxydemeton-methyl gave 90 percent and parathion gave up to 90 percent. Campaigns against outbreaks were performed aerially with helicopters equipped with spray booms or by ground application using backpack sprayers. No secondary pest outbreaks were noted following the use of these chemicals. During recent years, sunn pest populations have remained low enough to make spraying unnecessary. The Lebanese Ministry of Agriculture is the only authority responsible for establishing sunn pest control programmes at the onset of a sunn pest outbreak.
Based on the current situation in Lebanon, requirements for a possible general control campaign against sunn pest are: helicopter-mounted spraying equipment; truck-mounted, powered spraying tanks; four-wheel-drive vehicles; powered individual sprayers; and pesticides.
The Ministry of Agriculture provides technicians and qualified labour as well as an entomology laboratory which is responsible for the follow-up studies on sunn pest activity in the field.
CONCLUSIONS
Wheat is produced in regions whose microclimate is favourable to sunn pest. The biology of the pest must be closely studied to obtain satisfactory results from control campaigns using chemical insecticides applied at the most opportune time.
RECOMMENDATIONS
A sunn pest national committee should be established in each Mediterranean country to facilitate the exchange of research results. Studies on biological control should be carried out and results compared with those of chemical control programmes. Assistance should be provided to countries with limited budgets. Scientific meetings should be organized so that experts from each country can exchange information.
A.I. Mohyuddin
INTRODUCTION
In Pakistan, the sunn pest Eurygaster integriceps Put. is restricted in distribution to the submountainous and mountainous areas in the north and northwest. It was a serious pest from the early 1940s to the 1960s. However, for the past two decades it has remained at economically insignificant levels.
STATUS OF WHEAT AND BARLEY IN PAKISTAN
Wheat is a staple food in Pakistan and is grown in all provinces. Data on the area under wheat and barley cultivation, grain production and the amounts of wheat and barley imported and exported are presented in Tables 23 to 27 which are based on Agricultural Statistics of Pakistan (Government of Pakistan, 1993).
Area cultivated
The area under wheat cultivation over the five years, 1987/88 to 1991/92 is given in Table 23. It increased from 7.3 million ha in 1987/88 to 7.9 million ha in 1990/91, with a slight decrease during 1991/92. Total grain yield has increased from 12.7 million tonnes to 15.7 million tonnes.
Barley is cultivated on a small scale in Pakistan. The area cultivated with barley decreased from 159 000 ha in 1988/89 to 157 000 ha in 1990/91, but increased to 160 000 ham 1991/92. Total grain yield increased from 112000 tonnes in 1987/88 to 140 000 tonnes in 1991/92 (Table 24).Yield increased by about 10 percent during this period. Demand for two-row barley is very low in Pakistan because alcoholic beverages are not widely consumed and there are few breweries.
TABLE 23 - Area under wheat cultivation, yield per hectare and total production over five years in Pakistan
|
Year |
Area ('000 ha) |
Yield (kg/ha) |
Total yield ('000 tonnes) |
|
1987/88 |
7308 |
1734 |
12675 |
|
1988/89 |
7730 |
1865 |
14419 |
|
1989/90 |
7845 |
1825 |
14316 |
|
1990/91 |
7911 |
1841 |
14565 |
|
1991/92 |
7878 |
1990 |
15684 |
TABLE 24 - Area cultivated with barley, yield and total production over five years in Pakistan
|
Year |
Area ('000 ha) |
Yield (kg/ha) |
Total yield ('000 tonnes) |
|
1987/88 |
145 |
771 |
112 |
|
1988/89 |
159 |
772 |
123 |
|
1989/90 |
155 |
849 |
131 |
|
1990/91 |
157 |
906 |
142 |
|
1991/92 |
160 |
875 |
140 |
Wheat varieties used in Pakistan
Some 30 wheat varieties are grown in Pakistan. Of these, 22 are regarded as high-yielding (Table 25) and eight as low-yielding. The approximate area under production with the various wheat varieties is given in Table 25. PK 81 is grown throughout Pakistan. Other varieties are confined to different agro-ecological areas, for instance: Pir Sabak 85 is cultivated on 65 percent of the area in the North West Frontier Province and Azad Kashmir; Chakwal 86, Barani 83 and Rawal 87 are cultivated in rain-fed areas of the Punjab and Azad Kashmir; and Pawan, Sarsabaz and Sindh 81 are extensively cultivated in southern Pakistan. Short-duration varieties, such as Faisalabad 83 and Faisalabad 87, are cultivated in cotton- and rice-rotation areas in the Punjab. In Baluchistan, where E. integriceps occurs, eight varieties are grown - Faisalabad 85, Punjab 85, Sarsabaz, Pawan, Zargon 79, Zimindar 80, Z.A. 77 and Kohinoor 83. Of these, Zargon 79 and Zamindar 80 are cultivated across 70 percent of the area.
TABLE 25 - High-yielding wheat varieties cultivated in Pakistan and the relative area under cultivation
|
Variety |
Where cultivated |
Percentage of area cultivated |
|
Pak 81 |
Throughout Pakistan |
52.0 |
|
Faisalabad 83 |
Throughout Punjab |
5.0 |
|
Faisalabad 85 |
Throughout Punjab |
5.0 |
|
Chakwal 86 |
Rain-fed areas of Punjab and Azad Kashmir |
2.0 |
|
Barani 83 |
Rain-fed areas of Punjab and Azad Kashmir |
3.0 |
|
Rawal 87 |
Rain-fed areas of Punjab |
4.0 |
|
Satluj 86 |
Central and southern Punjab |
2.0 |
|
Punjab 85 |
Baluchistan and central Punjab |
1.0 |
|
Pir Sabak 85 |
North-West Frontier Province and Azad Kashmir |
6.0 |
|
Sarsabaz |
Baluchistan, southern Sind and Azad Kashmir |
1.0 |
|
Pawan |
Baluchistan and southern Sind |
1.0 |
|
Sogat 90 |
Sind |
1.0 |
|
Sind 81 |
Sind |
1.0 |
|
Zargon 79 |
Baluchistan |
1.5 |
|
Zimindar 80 |
Baluchistan |
1.5 |
|
Z.A. 77 |
Baluchistan and Sind |
1.0 |
|
Kohinoor |
Baluchistan and Punjab |
1.0 |
|
Mehran 89 |
Sind |
0.5 |
|
Tandojam 83 |
Sind |
0.5 |
|
Khyber 87 |
North West Frontier Province |
1.0 |
|
Pasban 91 |
Recent release |
Not available |
|
lnqlab 91 |
Recent release |
Not available |
|
Low-yielding varieties |
All provinces |
7.0 |
The low-yielding wheat varieties grown in Pakistan are Sonilika, Mexipak, Dirk, Lu-26, Blue silver, C591 and other tall verieties, SA 75, SA 42 and Lyallpur 73.
TABLE 26 - Area planted with high- and low-yielding varieties and yield over five years in Pakistan
|
Year |
High-yielding varieties |
Low-yielding varieties |
||
|
Area ('000 ha) |
Yield (kg/ha) |
Area ('000 ha) |
Yield (kg/ha) |
|
|
1987/88 |
6876 |
1797 |
432 |
732 |
|
1988/89 |
7085 |
1955 |
644 |
870 |
|
1989/90 |
7279 |
1895 |
565 |
925 |
|
1990/91 |
7377 |
1 902 |
534 |
996 |
|
1991/92 |
7370 |
2058 |
508 |
1024 |
The area planted with low-yielding varieties is small, comprising about 7 percent of the total area under wheat cultivation (Table 26).
Production
Production increased from 1 734 kg per hectare in 1987/88 to 1 990 kg per hectare in 1991/92. Total production also increased gradually over those five years (Table 23).
Imports and exports of wheat and barley
In 1987/88, Pakistan exported 2 000 tonnes of wheat. Since 1988/89, however, the country has imported wheat (Table 27). Because barley is an insignificant crop in Pakistan, import and export data are not available, but it is probably neither imported nor exported.
Major pests and diseases
Wheat pests have been reported by Janjua and Khan (1955), Hashmi, Hussain and Ulfat (1983), the Commonwealth Institute of Biological Control (CIBC, 1969), Abbas and Shabbir (1961) and Ahmad and Jabbar (1972). Janjua and Khan considered wheat to have no serious pests in Pakistan. With the introduction of high-yielding varieties and changes in cultural practices, some pest problems arose in specific regions. Introduction of thick-stem varieties and the practice of sowing wheat after harvesting rice without removing the stubble resulted in problems with the stem borer, Sesamia inferens Walk. Insect pests recorded from Pakistan are listed in Table 28. Almost all pests recorded are polyphagous.
TABLE 27 - Wheat imports and exports for five years in Pakistan
|
Year |
Export ('000 tonnes) |
Import ('000 tonnes) |
|
1987/88 |
2 |
0 |
|
1988/89 |
0 |
1766 |
|
1989/90 |
0 |
1603 |
|
1990/91 |
0 |
627 |
|
1991/92 |
0 |
1640 |
Ten diseases of wheat and four of barley are listed in Table 29. Hafiz (1986) described their symptoms and discussed control measures.
No estimates of the losses caused by pests are available. Losses probably range from 5 to 10 percent.
Government policy on wheat and barley
The Government of Pakistan is striving for self-sufficiency in wheat production. Since 1987/88, there has been a gradual increase in yield and production (Table 23). Wheat is still imported, however, probably because of increased demand from an expanding population. Increased production of wheat and barley has mainly been the result of increases in area planted with these crops, improved cultural practices and incentives provided to farmers, such as loans. The Pakistan Agricultural Research Council in Islamabad prepares annual recommendations on the suitability of different varieties for various agro-ecological areas, with information on the proper time of sowing, irrigation, treatment of seed, application of fertilizers, etc.
THE SUNN PEST PROBLEM
History and geographical distribution
Eurygaster integriceps Put. has been reported from Eastern Europe, Asia and southern areas of the former Union of Soviet Socialist Republics (Commonwealth Institute of Entomology, 1976). In Pakistan, it is confined to mountainous and submountainous areas (Figure 10). It was first reported in Baluchistan in 1937 as Eurygaster maura L. (Janjua and Khan, 1955). Khan (1963a) studied its distribution in Baluchistan and North-West Frontier Province (NWFP). He recorded sunn pest in the Sibi district, the Ziarat valley and the Fort Sandeman district of Baluchistan and, for the first time, in Landi Kotal (Khyber Pass), Wana (South Waziristan) and, in low numbers, in NWFP. Five years later (1968), he reported it as a serious pest of wheat in NWFP, mainly in the Peshawar and Dera Ismail Khan areas. Abbas and Shabbir (1961) also reported sunn pest from the Loralai and Mastung areas of Baluchistan. Cheema et al. (1973) first reported sunn pest in Parachinar (Kurram Agency), Abbottabad (Hazara district), Kashmir and Swat. A record from Rasul (Punjab) by Brown and Eralp (1962), was based on a damaged specimen in the Natural History Museum of London and appears to have been made in error.
TABLE 28 - Insects of wheat in Pakistan
|
Order/Family |
Species | |
|
Feed on leaves and/or stems |
| |
|
Collembola |
| |
|
|
Sminthuridae |
Sminthurus viridis (L.) |
|
Orthoptera |
| |
|
|
Acrididae |
Aiolopus thalassinus F. |
|
|
Chrotogonus trachypterus (Blanchard) | |
|
|
Schistocerca gregaria (Forskal) | |
|
|
Gryllidae |
Acheta domesticus (L.) |
|
|
Gryllus bimaculatus DeGeer | |
|
Isoptera |
| |
|
|
Termitidae |
Microtermes obesi Holmgren |
|
|
Odontotermes obesus Ramb. | |
|
Thysanoptera |
| |
|
|
Phlaeothripidae |
Haplothrips priesnerianus (Begnell) |
|
|
Thripidae |
Anaphothrips sudanensis Trybom |
|
|
Bregmatothrips brachycephalus (Sunsher) | |
|
|
Taeniothrips flavidulus (Begnell) | |
|
Hemiptera |
| |
|
|
Aphididae |
Aphis maidis Fitch |
|
|
Diuraphis noxia (Mordvilko) | |
|
|
Rhopalosiphum rufiabdominalis (Sasaki) | |
|
|
ft pad/(L.) | |
|
|
Schizaphis graminum (Rondani) | |
|
|
Sipha maydis passerini | |
|
|
Sitobion avenae (Fab.) | |
|
Cicadellidae |
Amrasca sp. | |
|
|
Balclutha hebe (Kirk) | |
|
|
Cicadella sp. | |
|
|
Exitianus sp. | |
|
|
Macrosteles sp. | |
|
|
Orosius albicinctus Dist. | |
|
|
Psammotettix alienus (Dahlbom) | |
|
|
Zyginidia quyumi (Ahmad) | |
|
|
Cixiidae |
Ollarus lodgarti Dist. |
|
|
Coreidae |
Cletus signatus Walk. |
|
|
Delphacidae |
Sogatella sp. |
|
|
Sogatella catoptron Fennah | |
|
|
Lophopidae |
Pyrilla perpusilla (Walker) |
|
|
Pentatomidae |
Bagrada hilaris (Burmeister) |
|
|
Eurygaster integriceps Put. | |
|
Lepidoptera |
| |
|
|
Lymantriidae |
Euproctis fraterna Mo. |
|
|
Noctuidae |
Agrotis ipsilon (Hufn.) |
|
|
Agrotis segetum (Denis & Schiff.) | |
|
|
Agrotis spinifera (Hubner) | |
|
|
Helicoverpa armigera (Hubner) | |
|
|
Mythimna separata (Walk.) | |
|
|
Ochropleura flammatra (Denis & Schiff.) | |
|
|
Spodoptera exigua (Hubner) | |
|
Coleoptera |
| |
|
|
Chrysomelidae |
Pechnephorus sp. |
|
Diptera |
| |
|
|
Agromyzidae |
Cerodontha incisa Meigen |
|
|
Phytomyza atricornis auctt. | |
|
Stem borers |
| |
|
Lepidoptera |
| |
|
|
Noctuidae |
Sesamia inferens Walk. |
|
|
Pyralidae |
Child partellus Swin. |
|
Diptera |
| |
|
|
Muscidae |
Atherigona sp. |
FIGURE 10 - Distribution of E. integriceps in Pakistan
TABLE 29 - Diseases recorded on cereals in Pakistan
|
Common name |
Organism involved |
|
Wheat |
|
|
Loose smut |
Ustilago tritici (Pers.) Rostr. |
|
Flag smut |
Urocystis tritici Koern |
|
Septoria leaf spot |
Septoria spp. |
|
Root rot |
Helminthosporium sativum (Pamm) King & Bakke |
|
Black point complex |
Alternaria, Helminthosporium, etc. |
|
Bunt or stinking smut |
Tilletia tritici (Bjerk) Wint |
|
Partial bunt |
Neovossif indica (Mitra) Mundkar |
|
Rusts |
Puccinia spp. (3) |
|
Downy mildew |
Scleropthora macrospora (Sacc.) Shaw & Naras |
|
Ear cockle |
Tyienchus tritici (S.) Bast |
|
Barley |
|
|
Loose smut |
Ustilago nuda (Jens.) Rostr. |
|
Covered smut |
U. hordei (Pers.) Lagerh |
|
Leaf spot |
Helminthosporium sativum (Pam) King & Bakke |
|
Powdery mildew |
Erysiphe graminis hordei Marchal |
Genera and species involved
Brown and Eralp (1962) list seven species in the genus Eurygaster. In Pakistan, E. integriceps was reported as E. maura by Janjua and Khan (1955). Brown and Eralp (1962) made a critical study of the distribution of Eurygaster species. They stated that E. maura occurs in Turkey, Iran and Crete (Greece), and concluded that reports from Pakistan by Pruthi (1943), Samuel (1949) and Janjua, Mustafa and Khan (1947) were erroneous. Khan (1968) also confirmed that the species occurring in Pakistan was E. integriceps. Khan (1963b) reported that one specimen of Eurygaster testudinaria (Geoff.) was collected from NWFP, but Brown and Eralp (1962) reported it only from Turkey and Iran, and did not include Pakistan in its range. This record requires confirmation.
Economic impact and yield losses
E. integriceps is the most serious pest of wheat in the Near East and loss of the entire wheat crop has been reported in some countries (USDA, 1980). In Pakistan, barley matures earlier than wheat, and therefore is seldom damaged as seriously as wheat. Quantitative economic loss data resulting from sunn pest damage are not available for Pakistan. Loss estimates have been made by different workers. Janjua, Mustafa and Khan (1947) suggested a loss of 30 to 90 percent of the wheat crop in Baluchistan. Khan and Khan (1963) stated that damage varied from 15 to 90 percent during different years. At present, sunn pest causes no significant damage to wheat or barley in Pakistan.
Area infested over the past two decades
Janjua, Mustafa and Khan (1947) reported that sunn pest caused serious damage to wheat in the Kohlu and Earkhan areas. Abbas and Shabbir (1961) reported that in 1958, the pest infested 12 500 ha. Khan (1968) reported that the highest sunn pest infestation occurred in 1962 when 212 insects per square metre were collected in the Kalat division. Sunn pest seems to have been much more serious from the 1940s to the late 1960s when various control measures were attempted, including hand picking of the bugs, than at present. No record of any serious sunn pest outbreaks is available after this time.
Varietal susceptibility to sunn pest
No studies on varietal susceptibility have been conducted in Pakistan.
Control measures
Chemical control. Abbas and Shabbir (1961) reported that in 195 8, malathion 50%, endrin 19.5%, toxaphene 60% and DDT 75% were sprayed on 12 500 ha in Baluchistan without conclusive results. In 1959, 500 ha of wheat were sprayed by air with malathion 50%, at the rate of 1 gallon (4.5 litres) per 4 hectares. This gave satisfactory control. In 1962, large-scale control operations were carded out in the Lahr valley using chlorthion and Dipterex (Khan and Durrani, 1963). Chlorthion gave 79 percent mortality in 36 hours and Dipterex killed 87 to 98 percent of the target population in 24 hours. At present, no spraying is conducted against sunn pest in Pakistan because populations remain below economic levels.
Biological control. No attempt has been made to develop biological control of the sunn pest in Pakistan. However, some of its natural enemies have been recorded. Samuel (1949) records the sarcophagid, Sarcophaga sp., parasitizing fifth-instar nymphs, with parasitism ranging from 0.5 to 1.5 percent. The house sparrow. Passer domesticus indicus, feeds on adults and nymphs, and Janjua, Mustafa and Khan (1947) recorded an unidentified asilid feeding on nymphs in addition to house sparrows.
Khan (1968) reported that natural enemies, especially egg parasitoids, exerted strong checks on sunn pest populations. He listed Phasia sp., Microphanurus sp. and several other general predators of sunn pest. Cheema et al. (1973) carried out a survey on pentatomids and their natural enemies. They recorded an unidentified nematode from adult sunn pest and recorded Chrysopa earned Steph. feeding on eggs and nymphs. The scelionid parasitoid, Trissolcus grandis Thomson, reared from other pentatomids, such as Carlocoris purpureipennis Deg. and Dolycoris indicus Stall., could be reared on E. integriceps eggs in the laboratory. This is a known parasitoid of sunn pest in Iran (Brown, 1962).
Cultural control. Janjua, Mustafa and Khan (1947) tried mechanical control and burning of weeds against sunn pest. For mechanical control, labourers were hired to hand-pick bugs and collect them in earthen pots or tins containing kerosene and water. The bugs were then purchased by the Department of Plant Protection. This activity was conducted on 155 ha in 1941, on 160 ha in 1942 and on 190 ha in 1943. 2.85 million bugs were collected and destroyed in 1941, 3.07 million in both 1941 and 1942 and 3.55 million in 1943. Abbas and Shabbir (1961) considered this method to be too expensive and aerial spraying was then tried as mentioned above.
Weed burning was evaluated from November to January. This involved burning the weeds on which sunn pest overwintered in the hills, but the impact on the pest population was not studied. Other methods were suggested by Khan (1968) including the use of early-maturing varieties and harvesting the crop at the milk stage.
Khan (1963b) tried two-step harvesting, as was done in the former Union of Soviet Socialist Republics, and concluded that this practice was not suitable for Pakistan because significant yield reductions resulted.
DISCUSSION AND CONCLUSIONS
Northern Pakistan seems to be the southern distribution limit off. integriceps. The submountainous and mountainous areas where it occurs constitute only 4 percent of the total area under wheat cultivation. The main wheat-growing areas seem to be ecologically unsuitable for sunn pest. Cheema et al. (1973) reported sunn pest from new regions in the northern hills in a survey conducted in 1969. It is not certain how long the pest had been present in that region. No systematic and intensive investigations have been made for natural enemies of the sunn pest in Pakistan. Cheema et al. (1973) carried out a survey of natural enemies of pentatomids, but over the two and a half years of the survey, sunn pest was actually studied for only a few months during 1969.
Khan (1968) stated that natural enemies, especially egg parasitoids, keep the sunn pest under control. Cheema et al. (1973) did not collect the eggs. When Trissolcus grandis reared from eggs of other pentatomids was offered sunn pest eggs, however, it readily parasitized them and developed normally.
Several egg parasitoids of sunn pest could probably be found if a thorough and intensive survey were carried out in the north and northwestern hills, where natural enemies keep the pest population under control. Pimentel (1963), while surveying 66 species successfully controlled by the introduction of natural enemies, pointed out that 39 percent of the pest species were controlled using natural enemies that originally attacked related species or genera. This is likely to be the case in Pakistan. After outbreaks lasting for more than 20 years, natural enemies of other pentatomids may have shifted to the sunn pest, resulting in its natural control. Pakistan may therefore be a good source of the natural enemies needed for biological control of sunn pest in other countries.
RECOMMENDATIONS
After the initial outbreak of sunn pest from the 1940s to the 1960s, sunn pest appears to be under natural control in Pakistan. A thorough search in Pakistan for its natural enemies is recommended.
REFERENCES
Abbas, H.M. & Shabbir, S.G. 1961. Distribution and control of Eurygaster spp. (wheat bug) in Pakistan. Agric. Pakistan, 12: 632-637.
Ahmad, M. & Jabbar. 1972. Some preliminary remarks on Zyginidia quyumi (Ahmad) an important pest of wheat and maize in some parts of Pakistan. Pak. J. Sci. Ind. Res., 15: 382-383.
Brown, E.S. 1962. Notes on parasites of Pentatomidae and Scutelleridae (Hemiptera: Heteroptera) in Middle East countries with observations on biological control. Bull. Entomol. Res., 53: 241-256.
Brown, E.S. & Eralp, M. 1962. The distribution of the species of Eurygaster (Hemiptera: Scutelleridae) in Middle East countries. Ann. and Mag. Nat. Hist. Series, 13, 5: 65-81.
Cheema, M.A., Irshad, M., Murtaza, M. & Ghani, M.A. 1973. Pentatomids associated with Gramineae and their natural enemies in Pakistan. Tech. Bull. Commonw. Inst. Biol. Control, 16: 47-68.
CIBC. 1969. Final report on survey of parasites of insect pests or cultivated and useful plants and survey of insects destroying weeds and their parasites. Pakistan Station, Commonwealth Institute of Biological Control, Rawalpindi, Pakistan. 234 pp. (Mimeograph)
Commonwealth Institute of Entomology. 1976. Distribution maps of pests, Series A (Agriculture) No. 40, Commonwealth Institute of Entomology, London.
Government of Pakistan. 1993. Agricultural Statistic of Pakistan. Ministry of Food, Agriculture and Cooperatives, Food and Agriculture Division, Islamabad, Pakistan.
Hafiz, A. 1986. Plant diseases. Pakistan Agricultural Research Council, Islamabad, Pakistan. 552 pp.
Hashmi, A.A., Hussain, M.M. & Ulfat, M. 1983. Insect pest complex of wheat crop. Pakistan J. Zool., 15: 169-176.
Janjua, N.A. & Khan, M.H. 1955. Insect pests of wheat in West Pakistan. Agric. Pakistan, 6: 67-74.
Janjua, N., Mustafa, A.M. & Khan, N.H. 1947. The biology and control of the wheat bug, Eurygaster maura Linn. in Baluchistan. Indian J. Entomol., 9: 73-83.
Khan, M.A. 1963a. Geographical distribution of Eurygaster Lap. in Pakistan. Agric. Pakistan, 14: 362-365.
Khan, M.A. 1963b. Two-step harvesting and its utility as a method of control of Eurygaster integriceps Puton in Pakistan. Agric. Pakistan, 14: 441-442.
Khan, M.A. 1968. Sunn pest Eurygaster integriceps Puton in Pakistan and its peculiarities. Agric. Pakistan, 19: 83-87.
Khan, M.A. & Durrani, N.A. 1963. Large-scale control of Eurygaster integriceps Puton with Dipterex and Chlorthion in Lahr area (Kalat Division) during 1962. Agric. Pakistan, 14: 215-220.
Khan, M.A. & Khan, A.R. 1963. Apparent damage by sunn pest (Eurygaster integriceps Puton). Agric. Pakistan, 14: 436-439.
Mohyuddin, A.I. & Greathead, D.J. 1970. An annotated list of the parasites of graminaceous stem borers in East Africa, with a discussion on their potential in biological control. Entomophaga, 15: 241-274.
Pimentel, D. 1963. Introducing parasites and predators to control native pests. Canad. Entom., 95: 785-795.
Pruthi, H.S. 1943. A new important pest of wheat in India. Indian J. Agr. Sci., 13: 232-234.
Samuel, C.K. 1949. Notes on Eurygaster maura L. (Pentatomidae) pest of wheat crop in India with keys to its varieties and to the species of Eurygaster L. Indian J. Entomol., 8: 174-177.
USDA. 1980. Pests not known to occur in the United States or of limited distribution. Sunn pest Eurygaster integriceps Puton (Hemiptera: Pentatomidae). United States Department of Agriculture, Cooperative Plant Pest Report, 5: 121-124.
K. Sheikh and M. Al Rahbi
INTRODUCTION
Wheat is fundamental to the Syrian economy and agricultural activities. It ranks first among cultivated crops, in terms of both production and area, because of its suitability to the Syrian Arab Republic's dry conditions and alluvial soil. More than 1.34 million ha of wheat are planted in the Syrian Arab Republic, with a total production of 2.1 tonnes. Grain yields have averaged 1 544 kg per hectare over the past ten years. In 1992, the wheat yield was 3 million tonnes (Figure 11).
FIGURE 11 - Area of wheat production in the Syrian Arab Republic, 1981 to 1990
Wheat production in the Syrian Arab Republic is concentrated in zones where annual rainfall is greater than 350 mm. Cultivating wheat in lower rainfall areas results in lower and more erratic yields. Figure 12 shows the distribution of wheat in the Syrian Arab Republic. Nearly half of the country's wheat is grown in Al Hassake province (the Al Jazira plains). More than one-quarter of the Syrian Arab Republic's production comes from the Aleppo and Idlib provinces, with the remaining wheat area distributed among the other provinces.
Expansion in wheat cultivation has recently been accomplished by growing high-yielding varieties developed by the Directorate of Agricultural Scientific Research of the Ministry of Agriculture and Agrarian Reform. The most important varieties are Bohouth 1, Bohouth 2 and Bohouth 4. Varieties that have been developed in collaboration with the International Centre for Agricultural Research in the Dry Areas (ICARDA) include Cham 1, Cham 2, Cham 3, Cham 4 and Cham 6, as well as high-yielding and well-adapted varieties such as Mexipak, Horani, Juri 69 and Jazzireh 17.
The area cultivated with barley in the Syrian Arab Republic fluctuates yearly, depending on prevailing climatic conditions. Usually, the area devoted to barley has been about the same as that for wheat, particularly in recent years. Figure 13 shows the changes in the area devoted to barley from 1981 to 1990.
FIGURE 12 - Area of wheat infested by sunn pest in the Syrian Arab Republic, 1981 to 1990
FIGURE 13 - Area of barley production in the Syrian Arab Republic, 1981 to 1990
In zones 2 and 3 barley cultivation ranks lower than wheat because it has relatively low water requirements. Ar Raqqah province ranks first among barley-growing provinces, followed by Hassake, Aleppo and Hama. Rain-fed conditions result in low and erratic yields, which range from 235 to 1 538 kg per hectare. From 1979 to 1988, barley yields averaged 671 kg per hectare (Figure 13).
Barley varieties grown in the Syrian Arab Republic are: Arabi Aswad, a relatively drought- and frost-resistant variety grown in northern and northeastern provinces; and Arabi Abiad, which is grown in inland regions and in southern areas of the Syrian Arab Republic.
Many factors are considered in the Syrian Government's plan for wheat and barley production when determining the location and size of cultivated areas. Self-sufficiency in cereal production is the first priority, and this would require production of more than 2.5 million tonnes a year of wheat There are also agricultural considerations; for example, wheat is grown in irrigated areas as well as in zones 1 and 2, while barley is grown in zones 3 and 4.
Wheat and barley are vulnerable to many insect pests and diseases. The pests vary from region to region and from year to year.
Insect pests. Eurygaster integriceps (sunn pest or suni bug), Zabrus tenebrioides (wheat ground beetle), Syringopais temperatella (cereal leafminer), Schizaphis gramminum (bird-cherry oat aphid), Rhopalosiphum maidis (corn-leaf aphid), Cephus libanensis (Lebanese wheatstem sawfly), C. pygmaeus (European wheat-stem sawfly), Mayetiola destructor, (Hessian fly), Phyllopertha nazarena (Nazarene chafer), Porphyrophora tritici (ground pearls) and Lemea. sp.
Fungal diseases. Tilletia caries and T. foetida (stinking smut of wheat), Ustilago hordei (covered smut of barley), U. tritici (loose smut), U. nuda (loose smut), Urocystis agropyri (flag smut), Puccinia striiformis (yellow or stripe rust), P. striiformis f. sp. hordei (yellow or stripe rust), P. recondita f. sp. tritici (brown or leaf rust), P. recondita f. sp. hordei (brown or leaf rust), P. graminis f. sp. tritici (stem or black rust), Erysiphe graminis f. sp. tritici (powdery mildew) and E. graminis f. sp. hordei (powdery mildew).
THE SUNN PEST PROBLEM IN THE SYRIAN ARAB REPUBLIC
Sunn pest is one of the most important insect pests of wheat and barley in the Syrian Arab Republic. It was recorded for the first time in 1909 at Muaret Numan, where it caused severe damage. In the spring of 1924, sunn pest infested 70 000 ha in Hama, Idlib and Aleppo provinces. The area attacked by the insect expanded to include the remaining regions and provinces. It has consistently infested the Jazira region since the 1940s. Since then, Syrian cereal cultivation has been susceptible to sunn pest depredations which vary, however, by year and location.
At the onset of organized sunn pest control, mechanical control methods were employed such as collecting the adults and nymphs. About 160 000 litres of sunn pest were collected in 1925 and 45 700 litres in 1926. Such methods seemed to give acceptable protection of cereal crops in subsequent years. Other agricultural methods were employed, such as replacing wheat by barley in sunn pest "hot spots". The Ministry of Agriculture and Agrarian Reform issued Decree No. 35 on 26 April 1937, reducing by one-quarter the area sown to wheat in infested regions. This decree was also effective, but the increasing demand for wheat in the Syrian Arab Republic eventually resulted in the decree being ignored. Since the 1950s, chemical insecticides have been examined and used. The good protection, relatively low cost and ease of application of chemical control resulted in its widespread and continued use.
The only serious attempts to develop biological control methods have been the studies carried out by Remaudière and Skaf, with funding from FAO. Their work was confined to studying the complex of sunn pest egg parasitoids and attempting to culture adults to obtain eggs for mass-rearing and release of parasitoids.
GEOGRAPHICAL DISTRIBUTION
Sunn pest is found throughout the main wheat- and barley-growing areas of the Syrian Arab Republic. An average of 526 000 ha is treated with insecticides annually. In 1991,140 000 ha were treated, of which 46 percent was in Hassake province, 27 percent in Aleppo province, 25 percent in Idlib province and 2 percent in other regions and provinces including Al Ghab and Es Suweida provinces (Figures 14 to 16).
Eurygaster integriceps Put. is the most important and predominant sunn pest species in the Syrian Arab Republic. In the Al Jazira area (Hassake province), E. integriceps overlaps with E. maura and E. austriaca. Some Aelia species, including A. acuminata, have also been reported in the Syrian Arab Republic, but do not exceed 1 percent of the total sunn pest population.
Sunn pest causes heavy damage to the crop from the moment it reaches wheat fields in the spring (during the tillering stage) until it migrates to hibernation sites just prior to harvest.
Once attacked by sunn pest, the main stem of the wheat plant dies. This results in increased tillering and reduced grain yield. Overwintered adults feeding during the booting stage cause white grain heads. If the sunn pest density is more than two insects per square metre, grain loss will exceed 5 percent.
FIGURE 14 - Wheat areas treated with insecticides in the Syrian Arab Republic, 1982 to 1991
FIGURE 15 - Distribution of wheat areas infested with sunn pest in the Syrian Arab Republic
Studies have shown that there was considerable reduction in crop weight resulting from the insects feeding on different developmental stages of cereals in the 1988/89 and 1989/90 seasons. Infestation levels were 12.93 and 4.57 percent, respectively, and led to reductions in grain weight of 3.99 and 1.52 percent. Sunn pest attack caused damage to the endosperm and to the embryo, which in turn led to germination losses of 33 and 63 percent, respectively.
FIGURE 16 - Geographical distribution of sunn pest infested areas in the Syrian Arab Republic
Studies at ICARDA showed that flour milled from attacked grain was unsuitable for bread-making.
Control methods used in the Syrian Arab Republic
Chemical control has been the main control method used since the 1960s. Control is usually applied when the insect reaches the economic thresholds shown in Table 30.
When egg parasitism ranges from 40 to 50 percent, chemical control is not recommended. This rate depends on climatic and plant conditions. In dry years, when the insect's effect on the plant increases, the economic threshold decreases by 25 to 50 percent, while it increases by the same amount in years with warm and wet springs. Control is applied once against adults, but may be repeated against nymphs. Insecticides used in controlling sunn pest are primarily organophosphates used at the manufacturers' recommended rates. The most important insecticides used in controlling sunn pest over the past ten years in the Syrian Arab Republic are shown in Table 31.
The chemicals used against sunn pest generally give good control when applied at recommended doses and with the correct timing.
Insecticides have affected bees in some areas (Al Ghab, Aleppo and Idlib provinces), as well as sheep and cattle when they are brought into fields before the pesticide has safely degraded.
The cost of spraying 1 ha against sunn pest is US$15, which includes the value of the insecticide, labourers' wages and equipment. The Government bears all costs for the control programme. Infestation levels of more than three adults or more than ten nymphs per square metre constitute an outbreak.
Extension programmes for sunn pest control provide technical brochures which are distributed throughout the country and are well used. In addition, there are extension programmes aimed at increasing farmers' awareness through television, newspapers and radio, which include instructions to be followed by farmers for a successful control programme.
There is also national and regional collaboration on sunn pest research and control and coordination with Turkey to determine the timing for initiation of spraying and its duration, especially when spray aircraft are used along the border between the two countries. Meetings are occasionally held with Turkish specialists on control methods and consistent economic thresholds are adopted by both parties.
Research on sunn pest in the Syrian Arab Republic is still in its early stages and is supervised by the Directorate of Scientific Agricultural Research at Douma. The most important research results from this directorate are summarized below.
CURRENT RESEARCH
The Directorate of Scientific Agricultural Research of the Ministry of Agriculture has conducted research on the sunn pest life cycle, including a morphological characterization of the insect, dates of migration to and from winter hibernation sites and the rates of development of nymphs in the field. Other research topics undertaken include reproduction and factors affecting rates of egg hatch, population dynamics and the effects of the sunn pest on the wheat plant in the field. Research is also conducted on the efficacy of various insecticides on nymphs and adults.
TABLE 30 - Economic thresholds of sunn pest infestation in the Syrian Arab Republic
|
Insect instar |
Plant stage |
Economic threshold |
|
Adults |
Until the end of tillering |
>2/m2 |
|
Nymphs |
Flowering until grain filling |
5-10/m2 |
|
Nymphs and adults |
Milk stage and later |
5-6 nymphs/m2 |
TABLE 31 - Insecticides used against sunn pest in the Syrian Arab Republic
|
Trade name |
Common name |
Rate |
|
Dipterex 80% |
Trichlorfon |
1-1.5 kg/ha |
|
Zolon 35% ec |
Phozolon |
1.5-3 litres/ha |
|
Zolon 30% ulv |
Phozolon |
3.5g/ha |
|
Decis 5% ec |
Deltamethrin |
200-250 ml/ha |
|
Decis 1% ulv |
Deltamethrin |
0.75 g/ha |
|
Decis 1% dust |
Deltamethrin |
12.5 kg/ha |
|
Sumithion 50% ec |
Fenitrothion |
1 litre/ha |
|
Sumithion 40% ec |
Fenitrothion |
1.25 litres/ha |
|
Sumithion 95% ec |
Fenitrothion |
0.5 litres/ha |
|
Fastac 5% ec |
Alpha-cypermethrin |
1.5 litres/ha |
|
Fastac 1 % ulv |
Alpha-cypermethrin |
330 litres/ha |
|
Dursban 4% |
Chlorpyrifos |
1-2 litres/ha |
|
Lebaycid 50% |
Fenthion |
1-1.5 litres/ha |
|
Actellic 50% ec |
Pirimiphos-M |
0.5-2 litres/ha |
The colour of the adult sunn pest in the Syrian Arab Republic ranges from greyish-yellow to black About 75 percent of the adult population are brown. There are distinct morphological differences between males and females: there are ten spiracles on males and 12 on females; the last abdominal segment is larger in females than in males; and females are generally larger than males. The ratio of length to width averages 1:1.579 in male and female E. integriceps and appears to be characteristic of this species in northern areas of the Syrian Arab Republic.
Adults migrate to wheat fields when mean temperatures reach 14° to 15°C and the daily maximum temperatures reach 19° to 22°C. In the north of the Syrian Arab Republic, this generally occurs between 13 and 23 March. At this time, the population in the field gradually increases with continued migration. Subsequently, population density decreases as adults die after mating and oviposition. Adults disappear from wheat fields prior to the emergence of new-generation adults (around 18 May, although this may vary according to weather conditions).
Adults feed on wheat plants when the plants are in the tillering and stem-elongation stages, prior to reaching the reproductive state. Feeding periods prior to attaining the reproductive stage vary according to the prevailing climatic conditions at the study site and range from six to nine days.
Mating occurs during the morning on the top leaves of plants exposed to the sun; As observed in the laboratory, mating requires about 2.33 hours. Mating peaks at the same time as population density, when ambient temperatures range from 15.3° to 21.6°C.
After mating, females oviposit, laying five to 15 eggs per cluster in two to four parallel rows. The number of eggs/clusters varies according to the host plant. Females prefer smooth leaves for oviposition and the lower leaf surface is also preferred.
Females oviposit on grasses other than wheat, and the morphological and developmental condition of the plant is important. About 2.9 to 3.3 percent of eggs laid are sterile, while death of the embryo occurs in 0.9 percent, mechanical shattering in about 1 percent and 12.3 to 14.6 percent are parasitized. Three species of hymenopteran parasitoids - Trissolcus vassiilievi, T. grandis and T. simoni (Scelionidae) - attack the sunn pest. Parasitoid hatching rates range from 80.2 to 82.4 percent.
The first egg clusters may be observed in the field at the end of March. Egg density peaks 13 to 18 days after oviposition. Oviposition may continue for as long as there are adults in the field. Nymphs begin to appear around 10 April.
The sunn pest sex ratio varies over time. Each cohort of similar instars may have a different sex ratio, depending on the different activity rates of one of the sexes or on physiological factors such as the influence of the fat body on hibernation mortality and migration.
The sunn pest causes damage throughout its presence in the field. If the plant is attacked in the early growth stages, death of the main stem may result from feeding by adults. If attack occurs during booting, white ears may result. Feeding on grain results in a reduction in kernel weight and the deposition of proteolytic enzymes into the kernels, which lowers germination rate and ruins the grain for use in flour production.
Climate appears to affect the population structure of the sunn pest in the field more than crop status. The most important factor determining the concurrence of insects and susceptible plant stages is the time of migration, which depends on temperature, planting date and rainfall at the beginning of the season.
FUTURE GUIDELINES FOR SUNN PEST CONTROL IN THE SYRIAN ARAB REPUBLIC
The continued expansion of insecticide use poses many risks. It may lead to an imbalance in the ecosystem and result in further pest outbreaks. In addition, chemical control of sunn pest does not always protect wheat in the years subsequent to its application. New and alternative methods for controlling sunn pest are needed to maintain natural balances within the ecosystem. Guidelines for future sunn pest management are as follows:
· definition of the economic threshold for sunn pest;· appropriate adjustment in the method and timing of insecticide applications to control sunn pest while protecting natural enemies;
· study of the dynamics of the insect population in comparison with the phenological development of host plants to optimize planting and harvesting dates;
· conducting economic feasibility studies on the replacement of wheat with alternative crops;
· screening wheat varieties for sunn pest resistance;
· determining the most important non-wheat hosts for oviposition and how best to utilize them in controlling the insect;
· monitoring natural enemies, particularly egg parasitoids, to increase their impact on sunn pest populations.
Z. Simsek, H. Memisoglu and Y. Salçan
INTRODUCTION
Wheat and barley are grown on 9 351 000 ha in Turkey and yielded 16.2 million and 3.44 million tonnes, respectively, in 1989.
VARIETIES USED
Wheat and barley varieties cultivated in Turkey are shown in Table 32.
PRODUCTION
Although grain production varies across regions and years, average wheat and barley production was 1 759 kg per hectare and 1 351 kg per hectare, respectively, according to 1989 statistics.
WHEAT AND BARLEY EXPORTS AND IMPORTS
Wheat exports in 1992 were 3 678 028 tonnes, valued at US$323 919 000, while barley exports were 744 102 tonnes with a value of US$61 438 000. In 1992, wheat imports were 53 402 tonnes, valued at US$7 916 000, while 20 040 tonnes of barley were imported with a value of US$3 324 000.
MAJOR WHEAT AND BARLEY DISEASES AND INSECT PESTS
Ear diseases. Tilletia foetida (Waller.) Liro (common bunt), T. caries (D.C.) Tul (common bunt), T. controversa Kühn. (dwarf bunt) and Ustilago tritici (Pers) Rostr. (loose smut).
Leaf and stem diseases. Puccunia graminis tritici Eriks & Henn. (stem rust), P. striiformis West (stripe rust), P. reconditia tritici Rob. & Desm. (leaf rust), Erisiphe graminis tritici (D.C.) Wint. (powdery mildew) and Septoria tritici Rob. et Desm. (septoria leaf blotch).
TABLE 32 - Wheat and barley varieties cultivated in Turkey
|
Wheat |
Barley |
|
Kunduru 1149 |
Cumburiyet 50 |
|
Dicle 74 |
Kaya 7794 |
|
Gökgöl 79 |
Tokak 15737 |
|
Tunca 79 |
Ankara 86 |
|
Çakmak 79 |
Hamidiye 85 |
|
Berkmen 469 |
Obruk 86 |
|
Bakali 85 |
Bülbül 89 |
|
Ege 88 |
Zafer 160 |
|
Kiziltan 91 |
Yesilkoy 387 |
|
Sham-1 |
Kocaoglu 84 |
|
Bolal 2973 |
Erginel 90 |
|
Ankara 093/44 |
Bilgi 91 |
|
Orso |
Sahin 91 |
|
Lancer |
Yildirim |
|
Bezostaya-l |
Efes 1 |
|
Cumhuriyet 75 |
Efes 2 |
|
Kirkpinar 79 |
Efes 3 |
|
Haymana 79 |
|
|
Gerek 79 |
|
|
Kiraç 66 |
|
|
Gemini |
|
|
Kate A 1 |
|
|
Izmir 81 |
|
|
Çukurova 86 |
|
|
Marmara 86 |
|
|
Atay 85 |
|
Leaf blotch diseases. Puccunia graminis tritici Eriks & Henn. (stem rust), P. hordei Otth (leaf rust), Erisiphe graminis hordei D.C. (powdery mildew), Rhynchosporium secalis (Oud.) J.J. Davis (scald), Drechslera graminea (Rob. ex Schlecht.) (stripe disease), D. teres (Sacc.) Schömaker (net blotch) and D. sorokiniana (Sacc.) Subram & Jain (spot blotch).
Root rot diseases. Pythium graminicolum Subr., Rhizoctonia solani Kühn, Fusarium culjorum Smith, F. moniliforme Wollen, F. nivale (Fr.) Snyd. & Hans., F. graminearum Schwabe, F. roseum f. cerealis Snyd. & Hans., Ophiobolus graminis Sacc., Drechslera sorokiniana (Sacc.) Subram. & Jain and Cercosporella herpotricoldes Fron.
Important insect pests of wheat and barley. Eurygaster spp. (Heteroptera: Scutelleridae) (sunn pest), Aelia rostrata Boh. (Heteroptera: Scutelleridae) (cereal bug), Zabrus tenebrioides (Coleoptera: Carabidae) (wheat ground beetle), Pachytychius hordei Bridle (Coleoptera: Curculionidae) (cereal weevil) and Anisoplia spp. (Coleoptera: Scarabaeidae) (cereal chafer).
YIELD AND ECONOMIC IMPACTS OF PESTS
Yield losses caused by pests vary by region and year. In 1992, predicted losses to pests in the absence of any control action were US$2 880 000 for A. rostrata, US$44 800 000 for Eurygaster spp., US$3 926 400 for P. hordei and $3 926 400 for Zabrus spp. and Anisoplia spp.
GOVERNMENT POLICY ON WHEAT AND BARLEY PRODUCTION
Special importance has been given to increasing wheat and barley production. Consequently, farmers have been subsidized by the Turkish Government. In the most recent five-year development plan, the Government's goal is to increase wheat and barley production by 3.6 and 3.0 percent, respectively.
THE SUNN PEST PROBLEM
History
The most important pest of cereals in Turkey is the sunn pest, with the most common species being Eurygaster integriceps Put. E. integriceps outbreaks occurred between 1927 and 1929 in southern Anatolia and between 1939 and 1941 in southeast Anatolia. Outbreaks have also occurred up to the present. Populations of E. integriceps have increased since 1982 in Thrace, where they peaked in 1987, causing significant damage to the crop. Recently, sunn pest has become a problem in central Anatolia, especially in the provinces of Konya, Aksaray, Kirsehir and Ankara.
Geographical distribution
Distribution of Eurygaster spp. is shown in Figure 17. Three species of Eurygaster are common throughout the country. The most important and common species is E. integriceps, especially in southeast Anatolia. However, E. maura and E. austriaca occur throughout Turkey as well.
Economic impact and yield losses
Overwintered adults, nymphs and new-generation adults cause damage by feeding on wheat and barley throughout the plant's development. Overwintered adults can kill 7 percent of plant stems and 1.9 percent of ears. Nymphs at densities often per square metre may cause 2.26 percent crop loss until new-generation adults appear. Then the damage increases to 4.78 percent one week after their appearance and may reach 7 percent at harvest. When the density of fourth and fifth instars and new-generation adults is high, the crop may be entirely destroyed in the absence of control measures.
FIGURE 17 - Distribution of Eurygaster spp. in Turkey
Area infested by sunn pest over the last 20 years
The areas sprayed against sunn pest from 1972 to 1992 are listed in Table 33.
TABLE 33 - Area sprayed for sunn pest (Eurygaster spp.)
|
Year |
Area (ha) |
Year |
Area (ha) |
|
1972 |
54760 |
1983 |
584 596 |
|
1973 |
17724 |
1984 |
519113 |
|
1974 |
9 |
1985 |
497 996 |
|
1975 |
0 |
1986 |
477 496 |
|
1976 |
16 |
1987 |
513623 |
|
1977 |
4235 |
1988 |
653 572 |
|
1978 |
11 074 |
1989 |
734 324 |
|
1979 |
14470 |
1990 |
92499 |
|
1980 |
32390 |
1991 |
521 668 |
|
1981 |
252 806 |
1992 |
586 588 |
|
1982 |
466 624 |
|
|
Varietal sensitivity to sunn pest
No research has been conducted in Turkey on varietal resistance to sunn pest.
CONTROL PRACTICES
Pesticides and dosages
Pesticides and dosages used are given in Table 34. Applications are made either conventionally or, for large areas, with ultra-low-volume (ULV) systems mounted on aircraft. In small areas where aerial spraying is impractical, ground equipment is used.
Biological control
In some parts of Turkey, the egg parasitoid Trissolcus spp. is effective. Chemical control should not be applied against sunn pest when instars one to three are present in fields, when population densities of overwintered adults are 0.8, 1.0 and 1.5 per square metre and when egg parasitism is 40, 50 and 70 percent, respectively, for the first three instars. However, chemical sprays should be applied for the fourth and fifth instars, if necessary.
TABLE 34 - Insecticides used to control sunn pest in Turkey
|
Name/formulation |
Dosage |
Pest stage |
|
Fenthion 50% ec |
125 ml/ha |
1-5 instar nymphs |
|
Fenthion 50% ec |
180 ml/ha |
Overwintered adults |
|
Fenthion 5% p |
3 000 g/ha |
Overwintered adults |
|
Fenthion 37.5% ULV |
165 ml/ha |
1-3 instar nymphs |
|
Fenitrothion 50% ec |
100 ml/ha |
1-5 instar nymphs, new-generation adults |
|
Fenitrothion 3% p |
2 500 g/ha |
1 -5 instar nymphs, new-generation adults |
|
Fenitrothion 40% ULV |
165 ml/ha |
1 -5 instar nymphs, new-generation adults |
|
Cypermethrin 25% ec |
20 ml/ha |
1-3 instar nymphs |
|
Cypermethrin 25% ec |
30 ml/ha |
4-5 instar nymphs |
|
Cypermethrin 2.5% ULV |
180 ml/ha |
1-3 instar nymphs |
|
Deltamethrin 2.5% ec |
30 ml/ha |
1-3 instar nymphs |
|
Deltamethrin 2.5% ec |
50 ml/ha |
4-5 instar nymphs, new-generation adults |
|
Deltamethrin 05% ULV |
150 ml/ha |
1 -5 instar nymphs, new-generation adults |
|
Cyfluthrin KL 025% ULV |
50 ml/ha |
1-5 instar nymphs |
|
Cyfluthrin KL 025% ULV |
150 ml/ha |
1-5 instar nymphs |
|
Cyhalothrin 5% ec |
20 ml/ha |
1-5 instar nymphs |
In fields where parasitism is low and population densities of overwintered adults exceed the economic threshold of 0.8 adults per square metre, the most suitable time for spraying is when 40 percent of the sunn pest population consists of second-instar nymphs.
Cultural control
Although sunn pest control in Turkey is conducted under a general integrated pest management (IPM) philosophy, no special cultural control methods are applied.
Effectiveness of the control programme
If chemical control of sunn pest is conducted according to the recommended methods mentioned above, 100 percent control is possible. In 1992, US$40.5 million in crop value was saved by effecting timely sunn pest chemical control.
Extension services try to minimize the side-effects of spraying. Generally, aerial pesticide applications in large areas cause drift of pesticides to non-target areas and organisms. As a result, the balance between pests and their natural enemies is disturbed and new pests may appear in these areas. Farmers dealing with bees and silkworms have been warned about possible side-effects of pesticides used in sunn pest control programmes.
Cost of sunn pest control
In 1992 the total cost of sunn pest control was US$4 342 019.
SUNN PEST CONTROL PROGRAMME CURRENTLY USED IN TURKEY
The surveys mentioned were made before chemical control was applied, after which the sunn pest population was assessed and sunn pest mortality compared with previous years.
Counts are done in certain overwintering areas in spring and autumn of each year to assess the pest population for the following year. Results are compared with those of previous years. The migration from hibernation areas to the field is observed to determine the spring population density of sunn pest in the field. For this purpose, one or two overwintering areas are sampled. The starting date of migration from overwintering areas to fields is determined by observing the activity of the pest when the daily temperature maximum reaches or exceeds 15°C, usually in March and April. Successive counts are done from the beginning of migration until 90 percent of the overwintered population has left the overwintering area.
Field surveys
Surveys are conducted by trained personnel to determine the area to be treated. At the end of the surveys, if the population level of the overwintered adults is equal to or exceeds 0.8 insects per square metre, an egg parasitoid survey is conducted. If the percentage of parasitized eggs is low, chemical control is used.
Treatment activities
Sunn pest control in Turkey is designed to attack the first three instars. Chemical control begins when second-instar nymphs are observed and continues until fourth-instar nymphs are seen. However, if chemical control cannot be completed during this period, the insecticide applications may be continued through the fourth and fifth instars. Chemical application for young nymphs begins five to six days after eggs hatch in the sunn pest-infested area.
Sunn pest control in Turkey, where appropriate, is conducted using aircraft rented from the Ministry of Agriculture and Rural Affairs. In the case of irregular landscapes and small fields, however, ground equipment is used by farmers. The farmers are supplied with insecticides and equipment by the ministry.
Sunn pest control is carried out with the cooperation of the Ministry of Agriculture and Rural Affairs, researchers, extension services and farmers. Each has different responsibilities.
The costs involved in implementing the control were as follows: control with ground equipment cost US$586 892, based on $12.7 per hectare sprayed on a total of 46 712 ha; control using aircraft can be broken down into ULV applications and conventional sprays - ULV applications cost about US$6.20 per hectare, which when applied over 441 424 ha totalled US$2 736 828, and conventional aerial sprays cost about US$10.0 per hectare and were applied over 49 141 ha for a total cost of US$491 410. Total control costs from all forms of chemical application therefore totalled US$3 815 130.
RESEARCH PROGRAMME
Internal cooperative programmes
Sunn pest control is carried out with the cooperation of the ministry's research and extension services and farmers. Researchers are responsible for training extension personnel and cooperate with extension personnel in sunn pest surveys in hibernation zones and cereal fields. They observe the migration of sunn pest from overwintering areas to the fields and decide on the correct insecticide application timing. Application of chemicals is carried out by extension personnel. Organization and funds for pesticides, aircraft, fuel, communications, reporting, personnel, etc., are supplied by the ministry. In terms of regional cooperation, collaboration among plant protection directorates in provinces is organized by the plant protection research institutes. Inter-regional cooperation is organized by the ministry.
CONCLUSIONS
Sunn pest (Eurygaster spp.) is one of the most important insect pests of wheat and barley in Turkey. Its biology, ecology, epidemiology and control have been studied in detail. Research results have been put into practice and damage from sunn pest has been reduced, primarily by chemical spray programmes.
RECOMMENDATIONS
More information on the potential for biological control of sunn pest is needed. Particularly important areas are mass production of egg parasitoids, release techniques and methods of enhancing and preserving natural parasitoid populations.
Forecasting and warning systems require refinement, including the determination of epidemics and the establishment of meteorological stations, either in overwintering areas or in fields. Data obtained should be computerized and a network for sunn pest control should be established.
Resistant cereal varieties should be investigated.
Economic thresholds should be reviewed.
