V - Pests and Diseases

Some noteworthy insect pests of Prosopis juliflora from Rajasthan, India - Mohammad Yousuf and Meeta Gaur

Division of Forest Protection, Arid Forest Research Institute, Jodhpur 342008, India.

Introduction

Prosopis juliflora is a thorny, evergreen to semi-evergreen tree, growing up to 10 m in height, very common in arid and semi-arid zones. The tree has a great economic value, meeting a large part of the demand for fuelwood and also proving a versatile plant for afforestation of shifting sand dunes, coastal sands, eroded hills and river beds. This paper deals with important insect pests associated with P. juliflora in the arid tracts of Rajasthan. A detailed survey was carried out in various locations in and around Jodhpur, in arid western Rajasthan, to record the insect pests associated with P. juliflora, and the following important insect pests were recorded.

Pests of P. juliflora

(I) Oxyrachis tarandus Fabricius (Hemiptera: Membracidae)

Hosts: Acacia catechu, A. nilotica, Albizia chinensis, A. lebbek, Cassia fistula, Dalbergia latifolia, Prosopis juliflora, P. cineraria, Santalum album, Tamarindus indica.

Material Examined: India: Jodhpur; 20 male, 30 female; 14.viii.1993 on Prosopis juliflora; M. Yousuf.

This membracid pest is widely distributed in India and adjacent countries. The eggs are laid on shoots in a V-shaped slit and injury often results in the stunting or death of the infested shoot. The scar is used by other insects as a site of oviposition. The nymphs and adults feed gregariously on the sap of the shoot. The feeding insects excrete honey dew and are usually attended by ants.

Ovipositing broods of O. tarandus are found throughout the monsoon season. Hatching takes place a few weeks after egg laying, and nymphs pass through five developmental stages, and the life cycle is completed in 6 weeks (Beeson, 1941). Five generations are completed per year in northern India. Attacks can be fatal, the killing of entire trees of P. juliflora by this insect in Vrindaban plantation has been reported by Dwivedi (1993).

(II) Aleyrodids spp. (Hemiptera: Aleyrodidae)

Hosts: Acacia nilotica, A. senegal, A. tortilis, Albizia lebbek, Dalbergia sissoo, Prosopis cineraria, P. juliflora.

Material Examined: India: Jodhpur, AFRI nursery; several male, female and pupae on Prosopis juliflora and other host plants.

Infestation of white flies (Aleyrodids spp.) is very common on P. juliflora in plantations as well as in the nursery. Thousands of pupae have been observed, attached to the lower leaf surface mainly and to the upper surface rarely. White flies are polyphagous on the sap of leaves of a large number of species, but in plantations, mortality or severe damage has not been recorded. In the nursery of AFRI, Jodhpur, infestation of 40% of P. juliflora seedlings was recorded during June 1993.

(III) Taragama siva Lefevre; Beeson 1941: 478-479.

Hosts: Acacia nilotica, A. senegal, A. tortilis, Colospermum mopane, Moringa oleifera, Prosopis cineraria, P. juliflora, Tamarindus indica, Zizyphus mauritiana.

Material Examined: India: Jodhpur; several males, females and larvae on Prosopis juliflora and other host plants; vi-x.1993; M.Yousuf.

This pale brown Lasiocampid moth appears in the first week of July in Rajasthan, and complete defoliation by this pest has been recorded on P. juliflora. Fore wings expanse in adult female moth is 60-70 mm and in male it is 30-40 mm. Eggs are laid in rows or clusters. Fully grown larvae are brown, 50-65 mm long, with tufts of long hairs. Pupation occurs in papery cocoons.

(IV) Poekilocerus pictus Fabricius (Orthoptera: Aerididae).

Hosts: Acacia senegal, Calotropis spp, Prosopis juliflora, Tecomella undulata.

Material Examined: India: Jodhpur; Chokhan village, many males and females;

vii.1993; M.Yousuf.

A grass hopper with stout body about 60 mm long, blue-black or greenish with yellow markings. Antennae bluish, ringed with yellow beyond the basal third of their length. Head with a broad yellow band within each eye and tegmina are green with longitudinal and transverse yellow nurvures, apex reddish, wings brick red. Commonly known as the AK grasshopper, it is distributed throughout the tropical and sub-tropical plains and the desert areas of India. Both adults and nymphs feed voraciously on leaves and can skeletonise plants, with even the bark eaten in the case of severe infestation.

(V) Halys dentatus Fabricius (Cimex); Syst. Ent. 1775: 702.

Hosts: Acacia nilotica, Albizia lebbek, Casuarina equisetifolia, Morus spp., Prosopis juliflora, Santalum album.

Material Examined: India: Jodhpur; Several males and females on Prosopis juliflora; 2.X.1993; M.Yousuf.

Halys dentatus has a body 21 mm long and 9 mm wide between pronotal angles, dull ochraceous in colour, coarse and darkly punctate. The scutellum reaching over half of the abdomen is pale at the apex. The underside of the body and legs are ochraceous. Antennae are 5-segmented, apices of second and third and base of fifth segments luteous, second and fourth and third and fifth segments are subequal. The rostrum extends beyond the fifth abdominal segment. It is commonly known as the stink bug and is distributed throughout India.

(VI) Microtermes mycophagus Desneux (Isoptera: Termitidae).

Host: Prosopis juliflora plants.

Material Examined: India: Jodhpur; Jhalamand; 3 soldiers and 31 workers on Prosopis juliflora; 8.X.1993; M.Yousuf.

Head, eyes, antennae, mandibles and other body segments were similar to the description given by Roonwal and Bose (1964) for the same species. They are small, dull white, delicate looking termites which usually attack roots, stems and branches causing bark peeling and gum exudation from injured parts.

(VII) Eurybrachys tomentosa fabr.; 1775:324 (Hemiptera: Fulgoridae).

Hosts: Plants of Albizia lebbek, Calotropis gigantea, Cassia fistula, Cipadessa fruticosa, Crotalaria paniculate, Erythrina lithosperma, Santalum album, Scutia indica, Terminalia tormentosa, Vitex negundo, Zizyphus jujuba in peninsular India.

Material Examined: India: Jodhpur; Jhalamand; 5 females and several nymphs and egg masses on Prosopis juliflora; 2.X.1993; M.Yousuf.

This fulgorid bug can easily be distinguished by its head, pronotum and mesonotum greenish-olivaceous in colour, and metanotum, sternum and legs purplish red. Tegmina olivaceous green with small scattered spots and oblique transverse diseal fasciae flavescent; apical marginal area with double series of small shining black spots and without tegmina and 14 mm with tegmina. Eggs are laid in ovals, 30-40 per egg mass, with a covering of white flocculent wax, on the surface of the leaf or on the bark. One female lays 6 egg masses or about 200 eggs which hatch in 2-3 weeks. Newly hatched nymphs are gregarious. The feeding of this leaf hopper cheeks the growth of new shoots and if attack is prolonged and heavy, the leaves are shed and young shoots die back.

(VIII) Homoeocerus signatus Walker (Hemiptera: Coreidae).

Hosts: Acacia nilotica, Prosopis juliflora.

Material Examined: India: Jodhpur, Jhalamand, 1 female and several nymphs; 18.IX.1993; M. Yousuf.

The body is ochraceous with a broad basal fascia to the pronotum between the lateral angles. Corium pale, with a large transverse macular spot at inner angle. The head has a narrow fascia on each side before eyes and subgranulous lateral margins of pronotum black. Antennae with first and second joints pale castenous, apioes of 2nd and 3rd segments black, second joint longer than first, third a little shorter than first. Meso and metanotum with black spot on each lateral area. Body length 19 mm and breadth between pronotal angles 6 mm. Nymphs and adults of this species have been reported to cause mild damage to the saplings of A. nilotica and P. juliflora.

(IX) Drosicha spp. (Hemiptera; Margarodidae).

Hosts: Acacia nilotica, Albizia lebbek, Artocarpus integrifolia, Shorea robusta, Butea monosperma, Dalbergia sissoo, Eucalyptus spp., Ficus glomerata, Morus alba, Pongamia pinnata, Prosopis cineraria, Tamarindus indica, Terminalia arjuna, Toona ciliata, Zizyphus mauritiana.

Material Examined: India: Jodhpur; Kailana lake, several males, females and nymphs on Prosopis juliflora; 20.VII.1993; M.Yousuf.

A number of species have been reported from India, Drosicha stebbingi, D. dalbergiae and D. mangiferae being very common (Ali, 1970). The population of Drosicha spp. is very high in June-July, occasionally whole branches of a tree being covered with females and nymphs. The nymphs and adults cause considerable damage to young plantations of Prosopis juliflora.

Parasites of pests of P. juliflora

(i) Brachygrammatella aligarhensis

Hosts: Eggs of Oxyrachis tarandus on Prosopis juliflora plants.

Material Examined: India: Jodhpur; 1 male, 1 female; Ex egg of O. tarandus on Prosopis juliflora; 8.iii.1993; M. Yousuf.

Described by Khan (1976), this insect is characterised with its antenna having 2 segmented broadly attached funicles, club solid, fore wings broad, less than twice as long as wide; marginal veins with 21 setae. It has been reported as an egg parasitoid of O. tarandus (Yousuf and Shafee, 1987).

(ii) Ufens latipennis Yousuf and Shafee

Hosts: Eggs of Oxyrachis tarandus on Prosopis juliflora plants.

Material Examined: India: Jodhpur; 1 male, 1 female; reared from the eggs of Oxyrachis tarandus on Prosopis juliflora; 24.viii.1993; M.Yousuf.

This trichogrammated parasitoid is characterised with fore wings broad having marginal veins about as long as stigmal and pre-marginal veins separately. Female antenna with club 3 segmented and male antennae with club 4 segmented (Yousuf and Shafee, 1987).

(iii) Prospaltelle transvena Timberlake, 1926:312.(Timberlake, 1926).

Synonyms: Encarsia transvena (Timberlake): Gerling and Rivnay in viggiani; 1985: 90.

Hosts: Aleyrodids spp., Aleurocybotus indicus, Aleurodidus dispercus, Parabemicia myriciae.

Material Examined: India: Jodhpur, 5 males reared on Aleyrodids spp. on Prosopis juliflora; 26.vi.1993; M.Yousuf.

The specimens have been reared from white flies. These belonged to Encarsia transvena (Timberlake) (Polaszek et al., 1992). The species can be distinguished easily by having a tarsal formula of 5:5:5. Fore wings uniformly setose with an area of long setae. The head, thorax and gaster are largely pale. Female antennal club 3 segmented.

(iv) Brumus suturalis Fabricius; Kapur, 1942: 56-60.

Hosts: Aleyrodids spp., Bemisia tabaci, Aphids, Brachycaudus pruni, Coccids, Dialeurodes citri, Hyalopterus atriplicis, Myzus persicae, Pemphigus cynodnti, Phaenocoecus insolitus, Pseudococcus sp., Pyrilla perpusilla, Tetranychus bioculatus, Trialeurodes sp. (Kapur, 1966).

Material Examined: India: Jodhpur; 3 males, 2 females associated with Aleyrodids on Prosopis juliflora; 9.vii.1993; M.Yousuf.

The species can be distinguished easily by its prominent black eyes, and brownish yellow elytra. There is a median longitudinal black stripe, and one more black stripe on outer margin of each elytron, starting from humeral angle and ending before touching the tip of elytron.

Conclusions

Nine insect pests of P. juliflora and four pest parasites have been detailed in the present study, of which Taragama siva (Lepidoptera: Lasiocampidae) and Microtermes mycophagus (Isoptera: Termitidae) are the major pests. Detailed studies on the bionomics and control measures of these pests are required. The former is a serious defoliator while the latter attacks roots, stems and branches. White flies (Aleyrodidae) are minor pests of P. juliflora in plantations, but these can prove a serious pests if severe infestation is found at the nursery stage. Oxyrachis tarandus is also a minor pest but an infestation results in secondary attacks from borers through the slit prepared by O. tarandus females for oviposition. Poekilocerus pictus, Halys dentatus, Eurybrachys tomentosa, Homoeocerus signatus and Drosicha spp. are the other minor pests and are mostly polyphagous, also attacking Acacia spp. and other Prosopis spp.

Acknowledgements

The authors are greatly indebted to the Director, AFRI, Jodhpur, for providing necessary research facilities. Thanks are also due to the Head, Division of Forest Protection for encouragement and valuable suggestions. We are also thankful to Dr. N.S. Rathore, Z.S.I., Jodhpur for identification of termite material, and Dr. R.K. Avasthi, Vaish College, Rohtak, Haryana for the identification of Drosicha sp.

References

Ali, S.M., 1970. A catalogue of the Oriental Coccidae. Part III (Homoptera: Coccoidea). India Mus. Bull. 5: 74-79.

Beeson, C.F.C., 1941. The Ecology and Control of Forest Insects of India and the Neighbouring Countries. Vasant Press, Dehra Dun, India. 1007p.

Dwivedi A.P., 1993. Babul (Acacia nilotica). A multipurpose tree of dry areas. AFRI, Jodhpur (ICFRE publication). 226p.

Kapur, A.P., 1966. The Coccinellidae (Coleoptera) of the Andaman. Proc. Nat. Inst. Sci. India B. 32: 148-189.

Khan, M.Y., 1976. A new name for Brachygrammatella indica Khan (Hym: Trichogrammatidae). Curr. Sci. 45: 392.

Polaszek, A., G.A. Evans and F.D. Bennett, 1992. Encarsia parasitoids on Benisia tabaci (Hym.: Aphelinidae; Homoptera: Aleyodidae): A preliminary guide to identification. Bull. Ent. Res. 82: 375-392.

Roonwal, M.L. and G. Bose, 1964. Termite fauna of Rajasthan, India. Stuttgart 40 (3) (Heft 113) VI + 58, 5 pls.

Timberlake, P.H., 1926. New species of Hawaiian chalcidflies (Hymenoptera). Proc. Hawaiian Ent. Soc. 6: 305-320.

Yousuf, M. and S.A. Shafee, 1987. Taxonomy of Indian Trichogrammatidae (Hym.: Chalcidoidea). Indian J. Syst. Ent. 4: 52-200.

Pod and seed infestation of Prosopis juliflora with Caryedon serratus Oliver in the Thar desert - Satya Vir and S.K. Jindal

Central Arid Zone Research Institute, Jodhpur 342003, India

Introduction

Prosopis juliflora (Swartz) D.C. has an important place in the economy of the Indian desert. This plant has rendered a valuable service to poor rural people in the Thar desert by providing cheap and easily available fuelwood, facilitated by its fast growing nature in all arid habitats of the country. Besides this, the plant also retains a lush green colour during the summer when all other desert trees show signs of drought stress. During an intensive survey of insect pests of leguminous trees of the Thar desert, Caryedon serratus Olivier was found to infest the pods and seeds of Prosopis juliflora during hot summer months, and was identified as meriting further study.

C. serratus, primarily a storage pest of unshelled groundnut (Arachis hypogea) and tamarind (Tamarindus indica), has also been reported to infest seeds of Bauhinia spp., Cassia spp., Acacia nilotica and A. tortilis (Prevett, 1967; de Cellam, 1969; Arora, 1977; Singal, 1981; Robert, 1985; Singal and Toky, 1990). No information is however, available on the field status of this pest, especially on P. juliflora, in terms of percentage pod/seed infestation, quantitative losses, its carryover to stores and the effect on seed germination. This paper attempts to analyse these aspects of C. serratus infestation on P. juliflora trees.

Materials and methods

Experimental material comprised of 20 plants from different locations in and around Jodhpur, Rajasthan. One hundred pods from the canopy of each selected plant were collected at monthly intervals from the pod setting stage to pod maturity. C. serratus in the field was recorded by examining exit holes on the pod walls, however under storage conditions the adults emerge directly from the cocoons. Data for pod length, number of seeds per pod, and infestation of pods and seeds was taken, and loss in seed weight and seed biomass per plant were calculated following Satya Vir and Jindal (1994). Both infested and healthy seeds were tested for germination following ISTA (1985), after scarification with concentrated sulphuric acid. Means, coefficients of variation and correlation coefficients were calculated using standard statistical formulae.

Results and discussion

Mean, range and coefficient of variation of 8 characters of pods and seeds of P. juliflora studied are presented in Table 1. Pod length varied from 11.6 cm to 16.4 cm, with a mean of 24.8 seeds per pod. The infestation of pods ranged from 12% to 16% (mean 14.35%) and the infestation of seeds from 1.2% to 8.3% (mean 3.91%). Average weight of infested seeds was 2.19 g per 100 seeds compared with 3.30 g per 100 healthy seeds. The weight loss in infested seeds varied from 21.9% to 47.0% with the overall loss in seed biomass being 0.2-8.0% (mean 1.66%).

Table 1. Mean range and coefficient of correlation of 8 characters of P.juliflora.

Table 2. Correlation matrix of 8 characters of P. juliflora (* p <0.05, ** p <0.01).

Coefficient of variation was maximum for average pod length, number of seeds per pod and weight of healthy seeds (below 20%), which supports the date for interaction of sample and time of sample selection at uniform intervals. The coefficient of variation was high in the case of infestation of pods and seeds and loss in seed biomass, which is a clear indication that these characters depend upon the intensity of bruchid attack. Similar results have been obtained in other studies on Acacia senegal and Albizia lebbek (Satya Vir et al., 1995a; 1995b).

Pod length was directly correlated with the weight of healthy seeds (r = 0.51, p <0.05%) and infestation of pods was directly correlated with the weight of infested seeds (r = 0.62, p <0.01%) (Table 2). Observations recorded from pod setting to pod maturation (April to June) revealed that infestation of pods begins in April with 4.5% of the pods and 0.5% of the seeds infested, increasing to 22.0% and 2.0% respectively in May, and a further increase in infestation with the maturation of pods, with 46.3% of the pods and 3.5% of the seeds found to be infested with C. serratus in June.

The infested seeds did not germinate at all, as the embryo and part of endosperm had been eaten. In the case of non-infested seeds, the germination percentage was found to be 76%. The study thus clearly demonstrated that pod and seed infestation of P. juliflora with C. serratus is alarming, as the insect was found to flourish and multiply even during the hottest months of the summer when temperatures can reach 49^oC.

This also helps the insect to carry over from the field to stores of the primary hosts, the groundnut and tamarind, and other leguminous trees such as Prosopis cineraria and Albizia lebbek. It is hoped that these observations will initiate further field studies on the attack of bruchids on Prosopis spp., both indigenous and exotic, which are becoming very popular in afforestation and social forestry programmes.

Acknowledgements

The authors are grateful to Dr. M.L. Cox of C.I.E. London for identification of Bruchidae, and to the Director, Central Arid Zone Research Institute, Jodhpur for providing the necessary facilities for the study.

References

Arora, G.L., 1977. Taxonomy of the Bruchidae (Coleoptera) of northwest India: Part 1. Adults. Oriental Insects Supplement 7: 1-132.

de Cellam, J., 1969. Le Parc National du Nikilo-Koba (Senegal). Fascicule III.XVIII Coleoptera Bruchidae. IFAN-Dakar, Senegal.

ISTA (International Seed Testing Association), 1985. International rules for seed testing. Seed Science and Technology 13: 299-355.

Prevett, P.F., 1967. Note on the biology, food plants and distribution of Nigerian Bruchidae (Coleoptera) with particular reference to the Northern Region. Bulletin of Entomology Society (Nigeria) 1: 3-6.

Robert, P., 1985. A comparative study of some aspects of the reproduction of three Cacyedon serratus strains in the presence of its potential host plants. Oecologia 65: 425-430.

Satya Vir, D.R. Parihar and S.K. Jindal, 1995a. Studies on pod seed infestation with Bruchus bilineatophyous Pic. (Bruchidae) in Acacia senegal - an important tree of the Thar desert. Journal of Tree Sciences (in press).

Satya Vir, D.R. Parihar and S.K. Jindal, 1995b. Studies on Bruchus bilineatophyous Pic. (Bruchidae) infestation on pod/seed of Albizzia lebbek (L.) Benth in the Thar desert of India. Journal of Tropical Forestry (in press).

Satya Vir and S.K. Jindal, 1994. Fruit infestation of Acacia tortilis (forsk) Hayne by Bruchiduis andrewesi Pic (Coleoptera: Bruchidae) in the Thar desert. Forest Ecology and Management 20: 349-352.

Singal, S.K., 1981. Studies on the taxonomy of Bruchidae (Coleoptera: Bruchidae) from India. Ph.D. thesis, Punjab University, Chandigarh, India (unpublished).

Singal, S.K. and O.P. Toky, 1990. Carry over of bruchid, Caryedon serratus (Olivier) (Coleoptera) from field to stores through seeds of Acacia nilotica (L.) Willd in India. Tropical Pest Management 36: 66-67.

Insects associated with Prosopis cineraria in arid western Rajasthan, India - D.R. Parihar and M.P. Singh

Central Arid Zone Research Institute, Jodhpur 342003, India

Introduction

Prosopis cineraria is the most revered indigenous plant of the arid and semi-arid regions of western India. Very little information is available about the insect-plant associations in P. cineraria (Beeson, 1941; Mathur and Singh, 1960; Singh and Bhandari, 1986; Parihar, 1993). This paper describes the insect complex associated with this tree in the western part of the province of Rajasthan, India, divided by the role/influence of the insect on the host plant.

Insect pollinators

The flowers of P. cineraria are entomophilous and depend on insects for seed setting. Table 1 presents the insect species that were collected from P. cineraria inflorescences from a wide range of locations in western Rajasthan, India. Flowering occurs during the driest months of the year, and therefore the insect visitors would be those that are adapted to aridity. Thirty one species belonging to the orders Coleoptera, Diptera, Hemiptera, Hymenoptera and Lepidoptera were recorded visiting P. cineraria flowers. Bees were the most abundant insects, followed by the Dipteran flies (Parihar and Vir, 1993).

Gall forming insects

Galls reduce vegetative growth and seed formation in P. cineraria. The genesis of these growths is a result of a nutritional dependence of the causal organisms on plant tissues. Four distinct types of galls were be identified on P. cineraria in western Rajasthan (Parihar, 1994). Table 2 lists these, and other injurious insects of Prosopis described in the following sections.

(i) Galls on branches; were solid, hard, woody brown structures, caused by a chalcid, Pediobopsis sp. Galls measured 11.2-45.2 mm in length and 11-42 mm in breadth, and each had an oval larval chamber in the centre which opened externally through a small pore in the periphery through which the adults ultimately escaped. These galls were formed throughout the growing season. The chalcids were parasitised by Eurytoma sp.

(ii) Galls on rachis of leaflets; were globose, indehiscent and hard and measured 3.4-10.2 mm in length and 2.0-3.4 mm in breadth, and were prevalent throughout the growing season. The causal insect was found to be a cecidomyid, Contarinia prosopidis. The larval development took place in the gall cavity where they sucked sap from the tissues.

(iii) Galls on leaflets; were of variable size and developed on leaflets mostly during the rainy season. The causal organism was found to be Eriophyes prosopidis, a mite. The mites bred parthenogenetically, giving rise to large number of galls on the leaflets.

(iv) Galls on inflorescences; were oval and globose, masses of which were found developing on florets during the flowering season (April-May). Morphometrical studies revealed variability in shape, size and weight and also in the percentage infestation by 4 microlepidopteran insects which were the causal organisms. These were identified as Assura albicostalis, Anarsia triaenota, Eucosma lioplintha and Ascalenia sp. Larval development took place in the galls while they were still attached to the inflorescence. Older galls with fully developed pupae became detached from the inflorescence and the moths emerged from the fallen galls.

Defoliators

Chafers or Scarabaeid beetles constitute the most prominent group of defoliators. Of the large number of species of Scarabaeids, the more common ones were Lachnosterna consanguinea, Anomala sp., Adoretus sp. and Schizonycha ruficollis. These insects attacked the plants at the beginning of the monsoon season causing heavy defoliation.

A chrysomelid beetle, Cytra succineta was observed to frequently nibble tender foliage of P. cineraria. On young plants, grasshoppers imparted almost insignificant injury. Two species of Tettigonids, Holochlora indica and Latana inflata were found to feed on P. cineraria leaves and caterpillars of Taragama siva also fed occasionally. Locusts (Schistocerca gregaria) severely damaged the foliage when invasion occurred.

Table 1. Insects collected around floral parts of P. cineraria in western Rajasthan.

Sap suckers

A large number of sucking insects were observed on P. cineraria plants during different times of the year. Of these, the more important ones were Oxyrhachis tarandus, O. rufescens, Campyloma sp., Omanocoris versicolor, Homoeocerus sp., Declera levan, Oxycaraenus sp., Eurybrachys sp. and Macropsis sp. These insects sucked the sap from tender parts of the plant, and a few of these also injected toxins into plant tissues. The thrip, Frankliniella schultzei was also collected from the inflorescence, lacerating and licking the floral parts.

Wood borers

Both living and dead wood of P. cineraria was attacked by a variety of beetles, and this constituted the major pest category. Bostrychids bore into green shoots and twigs, making galleries in the sapwood during feeding. In the arid regions of Rajasthan, Sinoxylon pugnax and S. indicum have been recorded. Beeson (1941) also listed other Bostrychid beetles on P. cineraria; Sinoxylon anale, S. sudanicum, Trogoxylon auriculatum, T. spinifron, Lyctus africanus and Luctoxylon japonum. The larvae of Chrysobothris parvipunctata (Buprestidae) bored into sapwood and branchwood of standing trees, forming tunnels therein. Other Buprestids collected were Agrilus sp. and Anthaxia sp. Beeson (1941), and Mathur and Singh (1961) listed Chrysobothris beesoni and Melanophilla coriacea damaging P. cineraria trees. The most common wood borer beetles belonged to the Cerambycidae family. Stromatium barbatum, a polyphagous pest, damaging the wood of about 350 tree species, has been found damaging P. cineraria wood also in western Rajasthan. Another polyphagous Cerambycid, Celosterna scabrator is also a common pest of P. cineraria (Mathur and Singh, 1961). Two Coleopteran predators, Melambia sp. (Trogostidae) and Pseudobothrideres sp. (Colydiidae) were found predating Bostrychid and Cerambycid grubs.

Table 2. Injurious insects found on P. cineraria in western Rajasthan.

Subterranean insects

Among the subterranean insects, termites formed the main group. Considerable injury to newly planted seedlings and old trees, particularly during the drought periods, could be inflicted by the termite species Odontotermes obesus, Microtermes mycophagus and Microtermes obesi. Roonwal (1975) reported that Acanthotermes macrocephalus foraged on fallen seeds and bark pieces of P. cineraria.

Seed and pod borers

Bruchids were the most common seed and pod infesting insects. The infestation began when the pod was yet to ripen and continued until seeds mature with the insects inside. The common Bruchid species attacking P. cineraria were Bruchidius sp., Bruchus bilineatophygus and Caryedon serratus. Singh and Bhandari (1986) reported Caryedon longuidus larvae feeding on P. cineraria seeds.

References

Beeson, C.F.C., 1941. The Ecology and Control of Forest Insects of India and the Adjoining Countries. Govt. of India. 767p.

Mathur, R.N. and B. Singh, 1960. A list of insect pests of forest in India and the adjacent countries. India For. Bull. No. 171: 1-30.

Parihar, D.R., 1993. Insect fauna of khejri, Prosopis cineraria of arid zone. Indian Journal of Forestry 16: 132-137.

Parihar, D.R., 1994. Galls and gall-makers in khejri (Prosopis cineraria Linn. Druce) of arid zone of India. Annals of the Arid Zone 33: 313-317.

Prihar, D.R. and S. Vir, 1993. Pollinating insects of Prosopis cineraria. Annals of the Arid Zone 32: 267-268.

Roonwal, M.L., 1975. Field and other observations on the harvester termite, Anacanthotermes macrocephalus (Hodotermitidae) from Indian desert. Z. Angew Ent. 78: 424-440.

Singh, P. and R.S. Bhandari, 1986. Insects pest of Prosopis and their control. In: Proc. Nat. Symposium on the Role of Prosopis in Wasteland Development. Wasteland Board, Ministry of Environment and Forest. Govt. of India, New Delhi.

Taragama siva Lefebvre (Lepidoptera: Lasiocampidae): a serious defoliator of Prosopis juliflora - Mohammad Yousuf and Meeta Gaur

Division of Forest Protection, Arid Forest Research Institute, Jodhpur 342008, India.

Introduction

Prosopis juliflora, a thorny, large crowned, evergreen to semi-evergreen tree growing up to 10 m in height, is now acclimatised in a variety of soils, but especially in sandy soils in arid and semi-arid zones. It has proved to be a versatile plant for afforestation of shifting sand dunes, coastal sands, eroded hills and river beds (Muthana and Arora, 1983). Serious damage has been recorded on Prosopis plants due to defoliation by Taragama siva, generally known as a defoliator of Acacia spp. (Beeson 1941). It has been found however, that this insect prefers P. juliflora over Acacia spp., and caused complete defoliation in the former, not in the latter, if these species were found in the same area.

Nature of damage

Larvae feed upon the leaves of host plants. First instars or immature larvae cut the leaflets from the margins, but fully grown larvae start to feed upon the leaflets of a compound leaf of P. juliflora from the basal end. When all the leaflets are eaten on one side, feeding is started on the other side, and usually the single terminal leaflet is eaten last followed by the main stalk of the compound leaf. Thus the pest causes complete defoliation.

Morphology and life stages

Taragama siva is a large, densely scaled moth with a stout body, and the humeral lobes of the wings are prominent (Browne, 1968). The proboscis is atrophied. There are no ocelli and the antennae are bipectinated in both sexes. Hind wings have coastal areas greatly widened basally.

The freshly emerged female is yellowish brown, about 30 mm in length with fore wings expanding to 60-70 mm, almost uniformly light brown, except two light yellow linear demarcations extending from the touching points of the SC and R1, and one light yellow round spot in the middle of the wings. Hind wings with an expanse of 35-40 mm are uniformly pale except posterior margins with a brownish tinge. The freshly emerged male is also brownish yellow, about 25 mm in length, with a fore wing span of 30-40 mm, brownish two thirds antero basally and creamy yellow postero laterally with a conspicuous zigzag demarcation. Hind wings with an expanse of about 25 mm, uniformly pale except an inconspicuous light brown demarcation at the posterior margins. Male and female sex ratio in natural populations is found to be 57% and 43% respectively.

Soon after emergence mating takes place and after mating the female starts to lay eggs. Egg laying is usually completed within 2 to 4 days after emergence. The number of eggs laid by a female averages 100-120, with 172 being the maximum number recorded. Eggs are laid singly along the mid rib of the leaves or in clusters on leaves, are whitish in colour with a brown rosette shaped sculpturing at the anterior end, being about 1.8 mm in diameter. Hatching takes place in 10 to 20 days.

The first instar larva (5 mm) is yellowish brown in colour with dark brown head. In the next instars the colour of the larva changes to conspicuous yellow or brownish yellow. The fifth instar larva is 50-55 mm in length with a prominent head capsule. On the dorsum, there are two distinct rows of red tubercles from where a group of fine black hairs develops. Laterally there are tufts of long hairs at the side of each segment. On provocation, black bands of setae on the thoracic segments and white hairs are displayed. Three pairs of thoracic legs are present and abdominal prolegs are present on 3rd, 4th, 5th and 6th segment. Anal claspers or false legs are conspicuous. There are five instars. Pupation occurs in an elongated papery cocoon which is usually fastened with twigs. Occasionally cocoon formation takes place in crevices in tree bark, and pupae are also reported on stones.

Population dynamics

The moth appears in the first week of July. From August to October all the stages (eggs, larvae and cocoons) can be seen in thousands of P. juliflora and other host plants. Trees of P. juliflora can be found that have been completely defoliated and are covered with thousands of white papery cocoons. August and September is the peak period for the outbreak of this pest, and complete defoliation has been recorded in the same period. One generation of Taragama siva is completed in about 6 weeks and thus three to four generations are completed annually in Rajasthan.

Analysis of random samples of larvae and cocoons collected from the field revealed that there was a 14% mortality rate of larvae and pupae which was caused by natural enemies including dipterous larval parasites, and fungal and viral diseases. Some larvae were found hanging vertically with the tail region and head down wards being characteristic of viral diseases in Lepidoptera. Some of the mummified larvae were observed full of fungus. In some freshly dead larvae, maggots were found and after complete rearing of these maggots, dipterous parasites were collected and a further detailed study of these parasites is in progress.

Conclusions

Taragama siva is a serious defoliator of Prosopis juliflora and several other valuable forest tree species. Earlier data revealed that the pest was not so common and it was limited only to some localities, but it was found that the infestation of this pest is increasing rapidly and it has become a potential pest for other important tree species. Therefore, a detailed study on the bionomics, host range and control measures of this pest should be carried out with special reference to biological control measures.

Acknowledgements

The authors are greatly indebted to the director of AFRI, Jodhpur, for providing the necessary research facilities. Thanks are also due to the head of the Division of Forest Protection for encouragement and valuable suggestions.

References

Beeson, C.F.C., 1941. The Ecology and Control of the Forest Insects of India and Neighbouring Countries. Vasant Press, Dehra Dun, India. 1007p.

Browne, F.G., 1968. Pests and Diseases of Forest Plantation Trees. Claredon Press, Oxford. 1231p.

Muthana, K.D. and G.D. Arora, 1983. Prosopis juliflora (Swartz) DC. A fast growing tree to bloom the desert. CAZRI monograph No. 22, Central Arid Zone Research Institute, Jodhpur. 19p.

Injurious Hexapoda associated with Prosopis - M.P. Singh

Central Arid Zone Research Institute, Jodhpur 342003, India

Introduction

Prosopis species play host to a large number of insects, providing food, shelter and mating sites for these organisms. Insects and Prosopis plants have cohabited for periods extending into millennia during the process of evolution. Much of the genetic diversity in Prosopis owes its origin to the activities of insects. A majority of the insect species associated with these plants are benign, exerting no appreciable detrimental effects by virtue of their presence on the host plants. However, some of these insects do impart injury and therefore warrant consideration in the present context.

Prosopis spp and insect associations

Prosopis spp. have a very wide geographical distribution around the globe. The insect fauna associated with different species across various eco-geographical areas are predominantly local fauna adapted to these host plants over time, often with a limited distribution. A few of these, however, are ubiquitous. Accordingly, the number of insect species imparting injury to different species in different ecological regions is very large.

Cates and Rhoades (1977) and Kingslover et al. (1977) have described Prosopis leaves and fruits as a source of food for insects. Ward et al. (1977) furnished a check list of New World insects associated with Prosopis, while Johnson (1983) dealt with the seed insects of Prosopis species. Arruda et al. (1988) reported observations on P. juliflora in Brazil, while Mathur and Singh (1960) and Singh and Bhandari (1986) dealt with the pests of Prosopis species in India.

Insect attack on the different plant parts of Prosopis

The following description of injurious insects summarises the mode of pest infestation and the effect on different plant parts of different Prosopis species, specifically of the authors experiences in India. Table 1 contains a detailed list of the insects which commonly attack Prosopis species throughout the world.

Roots

Of the subterranean insects, termites form the most dominant group, with the initial phases of plant growth more prone to insect attack. Odontotermes obesus is the most common species in India. In nurseries, the grubs of Scarabaeid beetles may also destroy the roots. The most common species in western Rajasthan are Lachnosterna consanguinea and Anomala spp. Unidentified stout grubs measuring up to 12.5 cm in length and 7.5 cm in diameter were observed to infest ageing P.cineraria plants at a few locations around Jodhpur in 1990. The activity of the grubs allowed for secondary infection by fungi, resulting in the death of the plant. The grubs could not be reared to adult stage. In the U.S.A., the cicada Diceroproctus apache has been reported feeding on the sap of roots of various Prosopis spp. Caterpillars of Acrolophus spp. have also been found feeding on roots of Prosopis spp.

Stem and branches

A majority of the reported insects have been found inflicting injury to stem and branches. Coleoptera predominate, the activity of these insects being located under the bark, with a few insects feeding on the bark as well. The Bostrychids and Buprestids make small holes in the wood, thereby weakening the stem and reducing the timber value. Sinoxylon spp. are the most common Bostrychid and Chrysobothris spp. are the most common Buprestid. The most damaging group of beetles are the stem boring Cerambycids. The larvae of these beetles bore galleries in the stem and branches. Females of Oncideres limpida saw off the branches from the plants. Other species of the genus sever branches or girdle the twigs.

Among the sucking pests, the Coccoids inflict maximum injury owing to faster reproduction potential. The coccoids check plant growth; but there are fewer reports of wild plants dying due to their attack, unlike in crops and fruit plants. Heteroptera contribute in devitalising plants, with tender parts being more susceptible to their attack. Some of the species may also inject toxins into plant tissues.

Table 1. The injurious insects of Prosopis spp.

Leaves

Among the defoliators, the Scarabeid beetles, also called chafer beetles, and the Lepidopteran larvae are the major insect pests. Chafer beetles attack in groups while other types of beetles may feed isolated or independently. While the chafers attack in single invasions, most Lepidopteran larvae and also some beetle species often stay on the host plants for a couple of days. The plants of wild origin have an in-built capability of withstanding a certain degree of herbivory, therefore small leaf losses may not restrict the growth of adult plants, but defoliation may have a negative impact on younger plants.

Flowers, pods and seeds

Insect infestation on floral parts begins with the formation of floral buds and may continue until after the pods have matured. The coreid insect, Mozena obtusa pierces the buds of P. glandulosa and P. velutina sucking them dry, while Chlorochroa ligata pierce young fruits and cause them to abort. Larvae of Chaetocampa spp., Phalonia spp., Didugu argentilinea, Ofatulena spp. and Paramyelois spp., and the weevils of Apion spp. feed on the seeds of green pods. Bruchids infest the seeds at any stage after seed setting. Caryedon spp. are the most common bruchid species with a global distribution, with the bruchids often having a wide host range within the Leguminosae family.

References

Arruda, G.P. de, E.C. de Arruda, A.B.R. dos Santos and A.C.A. Holanda, 1988. Entomological observations. In: Habit, M.A. and Saavedra, J.C. (eds.), The Current State of Knowledge on Prosopis juliflora. FAO, Rome. pp327-333.

Cates, R.G. and D.F. Rhoades, 1977. Prosopis leaves as a source for insects. In Simpson, B.B. (ed.), Mesquite: Its Biology in Two Desert Scrub Ecosystems. Dowden, Hutchinson and Ross, Stroudsburg, Pa., U.S.A. pp61-83.

Johnson, C.D., 1983. Handbook on Seed Insects of Prosopis Species: Ecology, Control and Identification of Seed Infesting Insects of New World Prosopis. FAO, Rome.

Kingslover, J.M., C.D. Johnson, S.R. Swier and A. Teran, 1977. Prosopis fruits as a source for invertebrates. In Simpson, B.B. (ed.), Mesquite: Its Biology in Two Desert Scrub Ecosystems. Dowden, Hutchinson and Ross, Stroudsburg, Pa., U.S.A. pp108-122.

Mathur, R.N. and B. Singh, 1960. A list of insect pests of forest plants in India and the adjacent countries. Indian Forest Bulletin 171: 1-130.

Singh, P. and R.S. Bhandari, 1986. Insect pests of Prosopis and their control. In: Proc. Nat. Seminar on Role of Prosopis in Wasteland Development. Wasteland Board, Ministry of the Environment and Forest, Govt. of India, New Delhi. pp1-8.

Ward, C.R, C.W. O’Brien, L.B. O´Brien, D.E. Foster and E.W. Huddleston, 1977. Annotated check list of New World insects associated with Prosopis (Mesquite). Technical Bulletin - 1957, 4 SDA.

Diseases of Prosopis juliflora in Rajasthan - K.K. Srivastava and D.K. Mishra

Division of Forest Protection, Arid Forest Research Institute, Jodhpur 342003, India

Introduction

A review of literature (Bakshi et al., 1972; Bakshi, 1977; Bilgrami et al., 1979; 1981) reveals that very little work has been carried out on the diseases of P. juliflora in nurseries and plantations. The present study comprises of the etiology, symptoms and control measures of pathological infestations. Among the important fungal pathogens found on P. juliflora were; Botryodiplodia theobromae, Diplodia prosopides, Fusarium sp., Macrophomina phaesolina and Septoria prosopides.

Nursery diseases

Root rot

This disease is a serious problem in nurseries in the rainy season. It is caused by Fusarium sp. and was observed in 1-3 month old seedlings at Osian, Phalodi and Jodhpur forest nurseries, with an incidence of 20-25%. The symptoms were wilting of the leaves, diseased seedlings could be uprooted easily due to the rotting of the roots, and the phloem region could be peeled off easily with xylem vessels appearing black in colour.

The associated fungus was isolated on PDA medium and the white cottony growth was observed to contain white spores which were hyaline, septate and sickle-shaped. The disease can be controlled by adopting silvicultural practices for avoiding excessive humidity in nursery beds, and by soil drenching with Bavistin (0.1%) at monthly intervals. It has also been observed attacking Acacia nilotica (Srivastava et al., 1989).

Collar rot

This disease is being reported for the first time on P. juliflora and was observed in 6-9 month old seedlings. Appearing in dry conditions, the fungus attacks the collar region, which eventually becomes black due the accumulation of black pycnidia and the infected seedling eventually dies. The fungus was identified as Macrophomina phaseolina (Tassi) Goid, and microscopic observations revealed that each pycnidium contained minute hyaline conidia with pointed ends. No control measures were identified.

Plantation diseases

Stem canker

Though P. juliflora is a hardy tree species, sporadic incidences of canker formation were observed all over Rajasthan. Mechanically damaged trees were found to be susceptible to a weak parasite Botryodiplodia theobromae. The canker expands and the quality of the sapwood deteriorates. Callus formation was observed on affected parts and secondary infection of stem borers and termites was also observed on dead parts. The disease can be minimised by reducing excessive lopping and other physical injuries.

Leaf blight

This appears as light yellow to green coloured lesions on the leaflets, leading to complete defoliation in severe stages of infection. The pathogen was identified as Septoria prosopides, the development of which is favoured by high humidity. A foliar spray of copper based fungicides such as Blitox (0.2%) can successfully control the disease. Attacks on young plantations, and also leaf spot and blight diseases of Colletotrichum capsici, C. cymopsicola and Ravenelia spicigera have been observed in other parts of the country.

Twig blight and dieback

Young shoots usually injured by shoot borers were found to be susceptible to this pathogenic fungus, and the attack continues from the top of the tree in a downwards direction. The pathogen was identified as Diplodia prosopides Stev. & Peir., and affected parts exhibited minute black pycnidial bodies. It has also been noted in Maharastra and Delhi.

Acknowledgement

The authors are thankful to Dr. M. Yousuf for useful suggestions in the preparation of the manuscript.

References

Bakshi, B.K., 1977. Disease Insect Survey Report. Forest Research Institute, Dehra Dun, India. 46p.

Bakshi, B.K., R.M.A. Reddy, Y.N. Puri and S. Singh, 1972. Forest Disease Survey. Final Technical Report Pt-480. Forest Research Institute. Dehra Dun, India. 117p.

Bilgrami, K.S., Jamaluddin and M.A. Rizwi, 1979. Fungi of India. Volume I. Today and Tomorrow Printers and Publishers. New Delhi, India.

Bilgrami, K.S., Jamaluddin and M.A. Rizwi, 1981. Fungi of India. Volume II. Today and Tomorrow Printers and Publishers. New Delhi, India.

Srivastava, K.K., K.B. Kalyani and R. Rajarishi, 1989. Some noteworthy diseases of Acacia nilotica from south India and their management. Proceedings of a Seminar on Forest Production, Forest Research Institute. Dehra Dun, India.