Cross-Institutional co-operation in the development of new Bacillus thuringiensis products in Vietnam

The entomopathogen Bacillus thuringiensis (Bt) has been used in experimental production, screening programs, field tests, and sold commercially in Vietnam. 3 Vietnamese participants that now cooperate in a product development project have been involved in several phase of such programs: FIRI (Food Industries Research Institute), VNU (Hanoi University of Science, Vietnam National University) and NIPP (National Institute of Plant Protection). The present program profits from the experience in these institutions to make a coordinated effort to develop affordable and efficient Bt products to Vietnamese farmers for the control of diamondback moth (Plutella xylostella), and Helicoverpa armigera, Spodoptera litura, Spodoptera exigua and rice leaf folder (Cnapalocrocis medinalis). These insects are important leaf-eating, lepidopteran pests in Vietnam, and the latter are badly or not controlled with existing, commercial Bt products (without beta-exotoxin). For the selection strains for fermentation and product development, the specific activity for all screened strains are calculated. Contrary to LC-50, this figure is not dependent on fermentation yield, which is a function of suitability of the substrate for the strain. The specific activity can be calculated from LC-50 and fermentation yield measured as amount of cry-protein in the tested sample or product. It is a fast method for optimizing strain selection for insect species. The program includes the purchase of new equipment for the project as well as updating existing equipment used in the screening, bioassay and pilot production. Concept and strategy was developed with the European company Intelligent Insect Control. The Vietnamese Government and the Danish Aid Program under Danida support the project. (Résumé d'auteur)