Screening of Bacillus thuringiensis strains against economically important soybean lepidopteran insects in Argentina

SAUKA, D.H.; BENINTENDE, G.B.

Buenos Aires

Congreso; International Congress on Invertebrate Pathology and Microbial Control. 45th Annual Meeting of the Society for Invertebrate Pathology.; 2012

Society for Invertebrate Pathology

In Argentina, synthetic insecticides have been efficiently used, but their application has become problematic because of a range of factors, causing an increased relevance in the use of Bacillus thuringiensis products. Notwithstanding, most of these kinds of products must be imported, motivating corresponding increases in costs, and leading to a growing need for developing technologies that can achieve products based on B. thuringiensis in Argentina to be use in insect control programs. A total of 251 B. thuringiensis isolates were characterized by the presence of the cry1, cry2 and cry9 genes by PCR and PCR-RFLP analysis and for the presence of crystal proteins by SDS-PAGE. Those collected from the same sample, that harbor the same cry gene and crystal protein profiles were considered twin strains and discarded in order to overestimate distribution frequencies. The selected B. thuringiensis isolates were submitted to bioassays against two economically important soybean insects; the lepidopterans Anticarsia gemmatalis and Epinotia aporema. Most of the isolates reacted with the cry1 and cry2 primers, but only a few strains reacted with cry9 primers. This screening identified new B. thuringiensis isolates that showed high activity against the two lepidopteran species, which could be available as active ingredients of phyto-sanitary formulations, as well as their cry genes will be characterized and potentially used in Bt crops.