Introduction
Coordination and stimulations of nematode management activities in the Near East
Plant-parasitic nematodes must be addressed in crop production and in integrated pest management (IPM) systems if a sustainable agriculture is to meet world demands for increasing food and fibre production. On a worldwide basis, annual crop losses due to nematode damage have been estimated to average 12.3 percent, amounting to some US$77 million annually. The data available indicate that similar losses occur in the Near East. For example, estimated mean losses for vegetable crops due to nematode-related disease complexes in Egypt amounted to some 15 percent in 1986 with losses for field crops ranging from 5 to 20 percent. Economic damage of 40 to 50 percent can occur for the most damaging nematodes with sometimes complete crop losses. However, damage estimates obtained from carefully controlled experiments are still lacking for most regions. The subtle nematode symptoms and signs are often confused with nutrient deficiencies and other maladies, resulting in nematodes being overlooked by agricultural scientists as well as growers, There is a need for simple methods as employed in developed countries to estimate yield losses, to determine relationships with nematode density and appropriate methods to demonstrate improvement in crop growth when nematodes are controlled.
The main nematode problems throughout the region are caused by root-knot nematodes, Meloidogyne spp. Others include Rotylenchulus reniformis, Radopholus similis, Tylenchulus semipenetrans, Helicotylenchus multicinctus, Pratylenchus spp. and Ditylenchus dipsaci, and cyst nematodes (Globodera/Heterodera spp.) are important in the cooler areas.
The concept of integrating compatible tactics for controlling nematodes predates that of integrated pest management (IPM). The specific concept of integrated pest management is a relatively recent development in pest control. IPM consists of the development and deployment of pest control strategies and tactics that result in favourable socio-economic and environmental consequences. Theoretically, IPM is a holistic systems approach to limit pest damage to tolerable levels through a combination of tactics and techniques, including parasites and predators, host resistance, cultural practices, environmental modification, and pesticides where appropriate. Much of the emphasis has been on insects, with great opportunities remaining to include nematodes. A number of national and international IPM programmes have resulted in many research and extension programmes becoming more interdisciplinary.
Available strategies and tactics for controlling nematodes encompass resistant varieties, cultural practices, rotation, biological control and physical treatments such as solarization. Research in developed countries is targeted at the deployment of integrated management strategies that minimize the use of nematicides. Hence, research in such countries is increasingly appropriate to the needs of the Near East region where nematicides are often inappropriate or too costly for the grower. Nematode-control measures are employed at a minimal level in this region. This situation has resulted from a general lack of awareness and an urgent need to coordinate research and development and information transfer.
At present, cooperation and collaborative endeavours within and among the countries in the region are nearly non-existent. Therefore, the consultation urged all countries in the region to develop detailed plans to institute local and regional interdisciplinary research (and related training and extension), including economists, statisticians and sociologists (within and among institutions). These cooperative endeavours are essential to the proposed development of truly integrated, environmentally safe, nematode management systems. The long-term goal is to interface these programmes with comprehensive IPM systems for all major plant pests and pathogens. To achieve significant progress towards the goal of integrated nematode pest management, the respective countries are urged to adopt the following recommendations to advance the surely needed research/training/extension programmes that are essential to benefit their individual farmers and local/regional economies.
Research requirements
Much excellent taxonomic work has been accomplished in this region, and important surveys of the nematodes present in some countries have been made. The meeting recommended that the National Nematological Research Centre, University of Karachi, and the Nematological Research Centre, University of Cairo, be designated centres of excellence in nematode taxonomy and provide relevant taxonomic support to nematologists throughout the region.
There is a critical need to quantify crop losses and develop related damage functions and action thresholds. The meeting recommended the execution of carefully planned experiments to resolve these problems for the major nematode pests on a regional basis and to analyse and quantify the costs of nematode damage to the grower.
Nematicides should not be abandoned until effective alternatives have been devised, but control of their use is necessary; their use is much restricted by cost. Proper rotations need further development, coupled with studies of nematode host-ranges. Solarization is an important new control measure worthy of further testing in the region. The development and deployment of host resistance for nematode control is given a very high priority in many countries. In contrast minimal activities focus on this key strategy in the Near East. Nematodes in the region amenable to this control approach include root-knot, cyst, reniform and citrus nematodes. However, resistant cultivars should be introduced only after consideration of their suitability to the local environment and their resistance to the local nematode populations. Soil amendments, biological control agents, summer weed-free fallow, destruction of residual infected roots and clean planting stock should not be overlooked even by small growers. The meeting recommended that research programmes be established to develop integrated nematode strategies appropriate to the region, and that Jordan serves as a lead institution for work on soil solarization.
A key priority recommendation is the collaborative, interdisciplinary research (including inputs from economists, statisticians, sociologists within and among countries) required to develop effective integrated nematode/pest management programmes for the major crop-nematode combinations in the region.
Quarantine
Near East countries are unique in their opportunities to bring new, near pest-free land into agriculture. However, diverse topography and climate result in very different nematode communities in given regions. Because of these factors and the need to introduce plant germplasm with nematode resistance, carefully developed quarantine measures are needed. The meeting recognized the great importance of quarantine in preventing the introduction and spread of nematodes to new areas and recommended that international cooperation be sought to ratify the list of potential quarantine pests (see Table 31) in each country in the region. Also, national resources should be made available to enforce these quarantine regulations adequately and to extend surveys of nematode pests on key crops in all countries in the region. An additional regulatory effort should involve the establishment of at least one germplasm centre for importing and maintaining limited material of importance for the development of nematode resistance and for the provision of disease- and pest-free lines. Such a centre would require containment facilities to prevent the introduction of new pests.
Regulatory measures are also essential to ensure that seed and planting stocks are free of pests and disease. This programme would enable several countries to eliminate or greatly reduce current crop losses resulting from planting nematode-infected seeds (e.g. wheat seed-gall nematode) and various transplants (see Table 31).
Information transfer
A key deficiency in essential information exchange within the region involves the limited availability of recent publications and materials from developed countries. This problem is becoming more severe as related costs increase.
TABLE 31
List of potential nematode quarantine pests1 for the Near East region
|
A1 list2 |
A2 list3 |
|
Anguina agrostis |
Ditylenchus destructor |
|
A. funesta |
D. dipsaci |
|
Belonolaimus spp. |
Globodera rostochiensis |
|
Bursaphelenchus xylophilus |
G. pallida |
|
Heterodera glycines |
Heterodera avenae |
|
Meloidogyne chitwoodi |
H. schachtii |
|
Monotrichodorus spp. |
H. latipons |
|
Nacobbus spp. |
H. cajani |
|
Pratylenchus goodeyi |
H. zeae |
|
Rhaninaphelenchus cocophilus |
Meloidogyne naasi |
|
|
Radopholus similis |
|
|
Rotylenchulus reniformis |
|
|
Xiphinema index |
|
|
X. americanum |
1 Pests should be subjected individually to pest risk analysis.
2 Nematodes not existing in the Near East region.
3 Nematodes existing only in some countries of the region.
The restricted exchange of researchers and students with developed countries and the low level of the region in participation in international meetings and congresses are also important. The meeting recommended that all library facilities be enhanced and that at least two regional research centres develop linkages with developed countries to provide adequate resources for information transfer.
Extension
The extension worker is seen as a major link between the researcher and the farmer, therefore mutual trust is essential. Attainment of this trust requires an understanding of farmers' problems and attitudes as well as a thorough knowledge of agriculture. Support by the discipline specialist, including nematologists, is crucial for extension workers in securing this information base. Mechanisms of transfer of new information and production and pest-management practices are poorly developed in the region. It is recommended that nematologists in each country develop training programmes that would become key components of in-service extension worker training, and that timely extension brochures on nematodes be included.
Only minimal awareness of nematode damage to crops exists among farmers, extension workers and politicians. This deficiency poses numerous problems, such as securing essential funds. Once appropriate research is accomplished, it is recommended that extension workers be informed, and the damage being caused by nematodes and the benefits attained from their control be demonstrated to the farmer. More support and facilities result from increased awareness among growers and administrators. Chief nematologists also need to have basic training in agronomy and help improve overall farming productivity.
Staff requirements
With few exceptions, nematological expertise in the Near East region is inadequate, and the too few nematologists are poorly supported in terms of facilities and technical personnel. In most countries nematologists currently work in isolation. The meeting recommended that new nematologists be added or current researchers receive refresher education where warranted, to resolve research and extension needs as outlined. Nematology education should be encouraged and promoted at university and agricultural institution levels. The updating of training of institutional researchers and key technicians could be accomplished through regional workshops. It is further recommended that adequate laboratory facilities and equipment as well as land and materials for experimental plots be established as needed in each country.
The meeting further recommended that each country provide funding/facilities for a minimum two full-time nematologists for the proposed research/information/transfer programmes.
Publications
Relevant literature is frequently not accessible to nematologists throughout the region, and manuals and advisory leaflets, if available, are rarely written in a language that can be understood by extension workers and growers. However, nematology textbooks are becoming available in Arabic, and one nematological journal is published in the region. The meeting recommended that all researchers exploit the no-cost opportunities to publish in certain nematological journals and give greater consideration to developing needed educational articles.
Funding
There is a general need for increased funding for research, education and information transfer as related to integrated pest management. The consultation urged member countries to allocate adequate funds and seek donor support for national and regional programmes on integrated nematode management.
The consultation represented the first opportunity for many nematologists in the region to meet and discuss several nematode problems that are common throughout the Near East. The meeting agreed on the formation of a regional group on improved management of nematodes in the Near East. The group will have the following terms of reference:
· to promote the exchange of expertise between nematologists at all levels including extension, through training programmes and workshops;· to produce a biannual newsletter; compile a directory of all nematologists in the region including a brief outline of their scientific activities; and prepare a list of publications and reports for the region;
· to promote the coordination of collaborative research programmes inside and outside the region;
· to establish linkages for regional exchange of information and plant germplasm. An initial activity of this working group will be the distribution of books made available from an earlier international nematology project;
· to initiate and activate efforts in each country to enhance the awareness of appropriate officials and the general public of the opportunities and potential returns (up to 400-fold) of well-established integrated nematode/pest management programmes;
· to promote funding opportunities, especially for collaborative programmes.
Participation in the Near East Group for Improved Nematode Management would be open to all technical staff directly involved in nematode control in the region. The working group would be expected to function on an informal basis under the guidance of a steering committee. The following scientists were elected to this committee:
Dr M.A. Maqbool - Chairman
Dr M.A. El-Sherif - Secretary
Dr W.I. Abu-Gharbieh
Dr A.S. Al-Hazmi
