During discussions with regional experts, the role and use of BCA in rice is predicated on: • Relieving rice farmers from the ‘treadmill’ of continuous synthetic pesticide use. • Disavowing farmers of the belief that pesticide use necessarily increases yield. • Avoidance of broad-spectrum insecticide use within the first 40 days after transplanting. • Promoting the combination of cultural measures and BCA use, especially for seed treatment 32 3.1.2 Conclusions: development of BCA in rice production and against early stages of pest insects. • Observing the actual relevance of pests, weeds, diseases, rodents, etc., and taking appropriate measures only when necessary. With regard to management of BPH, BCA based on entomopathogenic fungi appear to be the most promising, but quality aspects need to be emphasised in the future, such as isolate or strain characterisation (genetics, biology, target specificity), in view of selection of the most effective products. Furthermore, formulations have to be improved and action thresholds in the field need to be confirmed for designing reliable application protocols. Although commercial products based on entomopathogenic fungi do already exist in some AMS (Appendix I), most of them are not registered for use against BPH. Therefore, private companies producing entomopathogenic fungi should be encouraged and supported to implement these improvements and further expand their portfolio especially for application in rice and against BPH. The application of parasitoids of the genus Trichogramma against rice stem borers appears to be straightforward and well elaborated in the field. Yet a broader application of this approach would require significantly reduced or no broad-spectrum pesticide applications in the future. The technological know-how to mass-produce Trichogramma is established in some AMS (e.g. Philippines, Thailand, and Indonesia); thus, the revival or extension of local production is feasible. Mass trapping based on pest species-specific pheromone lures appears to be another promising approach, which has been elaborated and field-tested in India. Large-scale applications (to increase efficacy and reduce costs for the farmer) should be field-tested in ASEAN to see whether the good experiences from India can be confirmed under Southeast Asian conditions. However, BCA-based IPM approaches require careful economic evaluation over several years, because the pest status of stem borers appears to be overrated at times and field experience indicates that removal of pesticide inputs alone could raise profitability for the farmer. To date, fungal diseases such as rice blast or sheath blight are still perceived to be difficult to treat by farmers and plant pathologists. The ABC database appears to reveal that rice blast is not ‘targeted’ by many BCA, despite its widely cited importance in AMS. However, solutions that work for managing fungal diseases in rice have been developed already: for instance, FAO has worked out management options for rice blast within its farmer-field-school programmes in Southeast Asia. Experiences from Vietnam indicated that rice blast usually could be managed with the use of resistant rice varieties coupled with careful nitrogen management and optimised seeding rate (59). BCA could complement this IPM approach by providing the necessary tools once the strategy above would not be sufficient to fend off disease. In particular, the field trials that were conducted by ABC with its partners in AMS while developing these Guidelines have revealed that the application of Trichoderma harzianum is a useful tool not only to control disease but to improve general plant
Implementing Biological Control Agents in the ASEAN Region
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