Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 19, 1995
Publication Date: N/A
Interpretive Summary: To be effective microbial insecticides (insecticides made from safe microorganisms such as viruses, bacteria and fungi) must still be active after being sprayed to control an insect pest. Sunlight, however, completely inactivates microbials 1 to 2 days after they are used. Dusts could enhance field persistence of microbial insecticides. In laboratory tests, experimental dust formulations of virus, talc and a UV-protectant exposed to sunlight were as stable as the same formulation not exposed to sunlight. Information currently available suggests an untapped, overlooked or neglected potential for use of dust formulations of baculoviruses and possibly other microbial insecticides.
Technical Abstract: Commercially available, microbial insecticides, are formulated either as sprayable liquids or wettable powders. Little research and development has focused on the possible use of dust formulations of microbial pesticides. Dust formulations of microbial insecticides may: recover more activity during production; increase shelf stability; disperse more uniformly over plants; and, provide more sunlight-UV protection. In this note we evaluated the simulated sunlight-ultraviolet (SUV) stability of dust formulations of inclusion bodies (PIB) of the singly-enveloped nucleopolyhedrosis virus of Helicoverpa/Heliothis (HzSNPV). Less than 5% of the original viral activity was still present after exposure of only PIB to SUV. Although individually adding a UV-protectant (carbon or Shade**TM) or an inert dust (talc) increased the SUV-persistence of PIB, they individually did not give the same level of protection as shielded PIB. Dust formulations of PIB + talc + a UV-protectant, however, were as active as PIB shielded from SUV.