GRANULAR FEEDING BAITS BASED ON BACILLUS-THURINGIENSIS PRODUCTS FOR THE CONTROL OF LEPIDOPTEROUS PESTS

Bacillus thuringiensis (Bt) spray products are devoid of protection ag ainst undesirable environmental conditions (UV light, heat, dew, phyll oplane materials), and are partially effective against bollworm larvae . To improve this situation, we embedded the spore-crystal product in a granular feeding bait formulation. The granules were made of wheat m eal used as both a carrier and a feeding stimulant; yeast extract also was incorporated into the granules, to stimulate larval feeding. A co mbination of Bt subsp. kurstaki and aizawai products was used in the g ranular formulation, to widen the host-range of the microbe against le pidopteran insects. The most effective size of granules, as studied in a controlled experiment in a dispersion tower, ranged between 149 and 210 mu. The granular product dusted on cotton was more active than th e Bt spray (Dipel) against Earias insulana. The present paper evaluate s other Bt adjuvants and formulations.