Mortality and feeding of mid-stadium larvae of Helicoverpa zea and Heliothis virescens fed a wild strain or a recombinant strain of Baculovirus heliothis expressing an insect-specific toxin of the scorpion Leiurus quinquestriatus hebraeus

Abstract

A recombinant of the Heliothis/Helicoverpa single-enveloped nucleopolyhedrosis virus (RcHzSNPV), carrying a gene encoding an insect-specific toxin from the scorpion, Leiurus quniquestriatus, herbraeus, significantly increased the rapidity of kill and reduced feeding by larvae af Heliothis virescens and Helicoverpa zea over that of its parental, wind-type strain (WtHzSNPV). The RcHzSNPV at 1.0 occlusion bodies/mm2 killed or paralyzed H. virescens and H. zea larvae ca. 1.5-fold and 1.7-fold quicer, respectively, than the WtHzSNPV strain. Larvae not exposed to virus produced 3-to 5-fold more frass than larvae exposed to RcHzSNPV, and ca. 2-to 3-fold more frass than larvae exposed to WtHzSNPV. Increasing the rapidity of kill and reducing larval feeding are attributes that enhance the use of recombinant baculoviruses as potential biorational pesticides.