Effect of Deltamethrin Treatment on Lepidopteran Larvae Infected with Baculoviruses Expressing Insect-Selective Toxins μ-Aga-IV, As II, or Sh 1

• Published in: Biological control 1998-05, Vol.12 (1), p.79-87
• Main Authors: Popham, Holly J.R., Prikhod'ko, Grigori G., Felcetto, Thomas J., Ostlind, Dan A., Warmke, Jeffrey W., Cohen, Charles J., Miller, Lois K.
• Format: Article
• Language: English
• Subjects: Autographa californicanuclear polyhedrosis virus; biopesticides; neurotoxins; pyrethroid; recombinant baculovirus; sea anemone toxin; spider toxin
• ISSN: 1049-9644; 1090-2112
• DOI: 10.1006/bcon.1997.0606

Modification of sodium channels by pyrethroids is promoted by channel opening. The insect-specific neurotoxins μ-Aga-IV from the spiderAgelenopsis aperta,As II from the sea anemoneAnemonia sulcata,and Sh I from the sea anemoneStichadactyla helianthusall increase sodium channel opening and so we tested each of them in combination with deltamethrin for synergistic insecticidal activity. We found that As II increased the insecticidal activity of deltamethrin against the blowflyLucilia sericata.We also examined the effect of deltamethrin on the infectivity and virulence ofAutographa californicanuclear polyhedrosis virus (AcMNPV) and recombinant toxin-expressing viruses in both dose-dependent and time-mortality studies. The recombinant viruses expressed chimeric synthetic genes for μ-Aga-IV, As II, or Sh I (genesmag4, sat2,andssh1,respectively). WhenTrichoplusia nilarvae were infected with a LC20of the recombinant viruses and treated with a LC20of deltamethrin in diet incorporation bioassays, the doses were strictly additive. A cooperative decrease in mortality rate was observed in droplet feeding bioassays when a low dose (LC20) of deltamethrin and high doses of toxin-expressing viruses were fed to larvae but this effect was host-dependent. InT. ni,only wild-type AcMNPV and a recombinant expressingmag4under very late viral promoter control exhibited reduced times in controlling host feeding and mortality in the presence of deltamethrin. ForHeliothis virescens,larvae infected withsat2-expressing viruses displayed shorter feeding times in the presence of deltamethrin than those infected with virus alone but only at very high virus doses.H. virescenslarvae infected with wild-type AcMNPV and amag4-expressing recombinant had shorter feeding times and also shorter effective and lethal times in the presence of deltamethrin. Our results indicate that coapplication of this pyrethroid will confer little or no advantage in field applications of recombinant baculovirus pesticides and that application of pyrethroids will probably have no adverse affect on recombinant virus efficacy unless it deters larval feeding and virus acquisition.