The compatibility of entomopathogenic microorganisms with thiamethoxam and other insecticides was studied in vitro and under field conditions. The microorganisms tested were: Aschersonia aleyrodis, Bacillus thuringiensis, Baculovirus anticarsia (NPVAg), Beauveria bassiana, Hirsutella thompsonii, Metarhizium anisopliae, Nomuraea rileyi, Paecilomyces farinosus, Sporothrix insectorum and Verticillium lecanii. Two concentrations of each product were tested in the laboratory, based on the maximum and minimum recommended rates for application in the field. The products were added to specific culture medium for growth of the entomopathogens. Reproductive and vegetative growth were evaluated for fungi, and colony forming units (CFU) were evaluated for bacteria. For the field test, CFUs were considered for both fungi and bacteria and caterpillar mortality for the NPV of Anticarsia gemmatalis (Hueb.). Results showed that: (1) the action of the pesticides on the vegetative growth and sporulation of the microorganisms varied as a function of the chemical nature of the products, its concentration and the microbial species; (2) thiamethoxam was compatible with all microorganisms studied; (3) endosulfan, monocrotophos and deltamethrin were the insecticides that most affected B. thuringiensis, B. bassiana, M. anisopliae and S. insectorum; (4) thiamethoxam did not affect the inoculum potential of B. thuringiensis, B. bassiana or M. anisopliae when applied to bean crop (Phaseolus vulgaris); and (5) thiamethoxam did not affect the efficiency of the nuclear polyhedral virus of A. gemmatalis.
Insecta; insecticide; microbial control; compatibility
