The Evaluation of Population Suppression by Irradiated Lepidoptera and their Progeny

Transcription

1 CRP Title: The Evaluation of Population Suppression by Irradiated Lepidoptera and their Progeny Section/Division: Insect Pest Control / Joint FAO/IAEA Division (NAFA) Project Officer: Jorge Hendrichs Period Covered: List of Participants: NAME (CSI) Rezaur, R. Arthur, V. Genchov, N. Yang, R. Zhang, H. Garcia-Lopez, J.C. Marec, M. Seth, R.K. Sutrisno, S. Esmaili, M. Abeeluck, D. Maung, N. Ahmad, N. Ocampo, V. Rosca, I. Animosov, A. Mansour, M. Dhouibi, M.H. Tuncbilek, A. INSTITUTE/COUNTRY Atomic Energy Research Establishment BANGLADESH CENA. Universidad de Sao Paulo BRAZIL Plant Protection Institute BULGARIA Zhejiang Academy of Agricultural Sciences CHINA Chinese Academy of Agricultural Sciences CHINA Instituto de Investigación de Sanidad Vegetal CUBA Czech Academy of Sciences CZECH REPUBLIC University of Delhi INDIA Center for the Application of Isotopes and Radiation INDONESIA College of Agriculture of Teheran IRAN Ministry of Agriculture and Natural Resources MAURITIUS Myanmar Agriculture Service MYANMAR Atomic Energy Agricultural Research Centre PAKISTAN University of the Philippines at Los Baños PHILIPPINES Research Institute for Cereals & Industrial Crops ROMANIA Institute for Plant Protection St. Petersburg RUSSIAN FEDERATION Syrian Atomic Energy Commission SYRIA Institut National Agronomique de Tunisie TUNISIA Turkish Atomic Energy Authority TURKEY

2 Cherni, A. Carpenter, J. Nguyen Thi, Q.H. Pham Van, L. Institute of Plant Protection UKRAINE US Department of Agriculture Agriculture Research Service U.S.A. Dalat University VIETNAM University of Hanoi VIETNAM Research Co-ordination Meetings: Date Location April 1995 Jakarta INDONESIA 2 6 September 1996 Vienna AUSTRIA 28 May 1 June 1998 Penang MALAYSIA Objectives of CRP (a) Overall The overall objective of project D.4.04: Feasibility Assessment, Field Evaluation and Implementation of Nuclear-Based Pest Control Systems is to assess the feasibility of SIT and supportive technologies through economic studies, field evaluation followed by implementation of area wide programmes to achieve environment-friendly pest control. (b) Specific The main objective of the CRP was to evaluate the potential of suppressing populations of pest Lepidoptera (caterpillars) in the field by inherited sterility methods, i.e. by rearing and releasing irradiated moths and/or their progeny in combination with other biological control methods. The ultimate goal is to have alternative environment-friendly control methods available to be able to reduce the vast quantities of insecticide that are used in agriculture to combat Lepidoptera pests, thereby disrupting beneficial insects, polluting the environment, causing pest resistance and affecting adversely the trade balance of developing countries because they must use hard currency to import them. Outputs (a) Research A previous CRP on Lepidoptera insect pests dealt with more basic or preliminary aspects of developing inherited or F-1 sterility technologies such as determining the effects of various dose levels on the resulting amount of sterility in the following generations in different Lepidoptera species. In addition, computerbased models were developed on the suppressive effects of F-1 sterility on field populations, and some studies were conducted in laboratory cages on the impact of inherited sterility on pest suppression. This follow-up CRP built on the results of the previous CRP and focused on addressing a more challenging and applied phase, consisting of developing rearing methods and evaluating the potential of suppressing populations of key pest caterpillar species in the field by inherited sterility, i.e. by releasing in the field irradiated moths and/or their progeny in combination with other biological control methods to assess the effects on pest populations.

3 Considerable progress was made in addressing this more applied phase of Lepidoptera inherited sterility research and development. These inherited sterility studies included some of the most important Lepidoptera pests world-wide. They included the diamondback moth of vegetables, the pink and the cotton bollworm, the sugarcane borer, the date or carob moth, the rice stem borer, the Asian and European corn borers, the apple codling moth, the stored grain moth, the peach borer, the tobacco caterpillar, the jute hairy caterpillar, and others. Many components were addressed, depending on the level of SIT technology development of the different pests species studied, such as mastering the various steps involved in the rearing and handling of different Lepidoptera pests, more cost-effective mass production systems on artificial diets, fine-tuning of irradiating doses to achieve sterility in females, however, at the same time only substerility in males, rearing of parasitoids or other natural enemies on the host species, etc., also collection of baseline data on the field populations, including the density of the pest and natural enemy populations and their rate of increase at the time that substerile moth and natural enemy releases are initiated. Furthermore, it also involved assessment of the behaviour of irradiated moths and their progeny under field-caged host conditions and in the field in relation to pheromone calling and response, capacity to disperse and to mate, to form spermatophores and to transfer sperm to the wild female spermatheca. For these studies, night vision equipment and special techniques such as mating tables involving female moths with clipped wings or on tethers, as well as analysis of spermatogenesis and chromosomes analysis were required. Finally, for some of the pest species with more advanced technologies, participants addressed the field assessment of suppression of wild populations, the interaction and synergism of inherited sterility with other biological methods and the overall economics of the approach in comparison to conventional suppression using insecticides. (b) Others Mass rearing, due to microbial diseases and other Lepidoptera-specific problems, is one of the main hurdles to be overcome to fully develop inherited sterility in Lepidoptera. A workshop on Lepidoptera rearing was therefore held in conjunction with the First RCM, to address these issues and to train participating investigators on good rearing practices and sterility assessment methodologies. Other outputs are the establishment of a network of scientists collaborating in this field in countries from Africa, Asia and Pacific, West Asia, Europe and Latin America. As a result of the CRP, several preparatory TC projects were initiated dealing with Lepidoptera pests (date moth in Tunisia and Algeria, diamondback moth in Mauritius and codling moth in Syria and South Africa). Effectiveness of CRP (a) In reaching Specific Objective The specific objective of the CRP, to further develop inherited sterility technology to allow evaluation of the potential of suppressing populations of pest Lepidoptera (caterpillars) in the field by inherited sterility methods, in combination with other biological control methods, was achieved at various levels of technological development for the different Lepidoptera pest species addressed. Considerable progress was made in relation to development of practical and cost-effective rearing and handling methods for a number of major Lepidoptera species and their natural enemies, opening the possibilities of future implementation of inherited sterility projects against some of these pests in a number of Member States. (b) In contributing towards Overall Objective The development of methodologies and their field evaluation to suppress pest Lepidoptera species by inherited sterility methods represents a major contribution towards the overall objective of project D Feasibility Assessment, Field Evaluation and Implementation of Nuclear-Based Pest Control Systems.

4 (c) Factors, if any, which adversely affected the effectiveness of the CRP It was very appropriate for the Agency to have undertaken the CRP because it addressed a clear case of unsatisfied demand. Lepidoptera pests are major potential targets of genetic control, however, for a majority of which considerable feasibility assessments and field evaluations are required before implementation of operational projects are possible. In order to obtain an overview of the potential of inherited sterility in many target Lepidoptera pests, the CRP had to be large and relatively broadly formulated. Obviously, with such a large group, there was considerable variation among participating researchers in progress made with their respective pest insects, reflecting not only the large differences in the biology of the different pest species, but also the varying state of knowledge on inherited sterility of the different target insects studied. Future CRPs on Lepidoptera inherited sterility should be limited to a few major pest species to focus R&D towards faster application of the technology in operational pest suppression programmes. Impact of the CRP Enormous losses in the production and marketing of food and fibre crops are caused by the caterpillars of Lepidoptera pests (moths). Currently, large quantities of insecticides are used to combat these pests, which are increasingly developing resistance to one or more insecticides. The heavy reliance on insecticides has significant negative impacts on the environment and destroys pollinators and natural enemies of these pests reinforcing the need for insecticides. SIT is less developed for application against these insects even though there is considerable potential for inherited sterility, a type of SIT. A previous CRP on inherited or F-1 sterility dealt with more basic aspects such as radiation dose effects on subsequent generations in different Lepidoptera species, modelling to assess the suppressive effects of F-1 sterility on field populations, as well as laboratory studies on the impact of inherited sterility. During this follow-up CRP, considerable progress was made in addressing a more applied phase of Lepidoptera inherited sterility R&D. These studies included some of the most important Lepidoptera pests would-wide such as the diamondback moth of vegetables, the pink and the cotton bollworm, the sugarcane borer, the date or carob moth, the rice stem borer, the Asian and European corn borers, the apple codling moth, the stored grain moth, the peach borer, the tobacco caterpillar, the jute hairy caterpillar, and others. Many components were addressed, depending on the level of SIT technology development of the different species studied, such as mastering the various steps involved in the rearing and handling of different Lepidoptera pests, more cost-effective mass production systems on artificial diets, fine-tuning of irradiating doses to achieve sterility in females however, at the same time only substerility in males, rearing of parasitoids or other natural enemies on the host species, etc., also collecting baseline data on the field populations, including the density of the pest and natural enemy populations and their rate of increase at the time that substerile moth releases are initiated. Furthermore, it also involved assessment of the behaviour of irradiated moths and their progeny under field-caged host conditions and in the field in relation to pheromone calling and response, capacity to disperse and to mate, to form spermatophores and to transfer sperm to the wild female spermatheca. Finally for some of the pest species with more advanced technologies, field assessments of suppression of wild populations were carried out, the interaction and synergism of inherited sterility with other biological methods was assessed and the overall economics of this approach compared to conventional suppression using insecticides. As a result of the significant progress made during the CRP, several preparatory TC projects were initiated at the request of Member States dealing with Lepidoptera pests such as date moth in Tunisia and Algeria, diamondback moth in Mauritius and codling moth in Syria and South Africa. Relevance of the CRP Lepidoptera pests are major potential targets of genetic control; however, for a majority of these, considerable additional R&D, feasibility assessments and field evaluations will be required before implementation of operational projects is possible. New CRPs in this field should focus on developing

5 complete packages of inherited sterility methodologies for the most promising species, including codling moth, gypsy moth and date moth. Recommended future action by Agency Future coordinated research such focus on increasing the applicability and cost-effectiveness of the inherited sterility against a few major Lepidoptera pests. One of these, for example, is the codling moth for which this technology is relatively advanced and there is a great potential for the application of codling moth SIT or inherited sterility. Nevertheless, this approach still has a low cost-efficiency, as well as various technical hurdles to be overcome. There are a number of promising research areas where the Agency can advance SIT s applicability and cost-efficiency: (a) development of a genetic sexing strain; (b) use of F1 sterility during part of the fruiting season; (c) use of diapause induction for stockpiling and for the development of new release strategies; (d) use of virus resistant strains; (e) use of transgenesis to introduce genetic markers,; (f) combining the SIT with other control tactics, e.g. pheromone mating disruption, release of parasitoids, insecticide (including IGR) treatments and tree banding; (g) aerial chilled-moth release systems and the competitiveness of the released moths; (h) benefits from releasing only sterile males instead of both sexes; (i) development of a trap to catch female moths, and (j) development of a method to assess the percent sterile matings in the field between wild females and sterile males.