Potential of a baculovirus of Autographa californica (Speyer) for the control of Chreysodeixis includens (Walker) and Anticarsia gemmatalis hübner (Lep.: Noctuidae)

Abstract

The potential of the nuclear polyhedrosis virus of Autographa californica (AcNPV) as a microbial insecticide for the velvetbean caterpillar, Anticarsia gemmatalis, and the soybean looper, Chrysodeixis includens, was evaluated under laboratory conditions, by selection of more virulent variants of the virus through its sequential passage by A. gemmatalis and C. includens. The AcNPV showed to be infective to both species with greater virulence to C. includens. The sequential passage of this NPV through A. gemmatalis and C. includens resulted in increased virulence to these hosts. After five passages, the lethal median concentration (LC₅₀) was reduced from 1,120.7 to 295.5 polyhedron inclusion bodies (PIB)/ml of diet for C. includens, and from 1,010.6 to 487.3 PIB/ml of diet for A. gemmatalis. When the AcNPV was passed through C. includens, it was not infective to A. gemmatalis. When passed through A. gemmatalis, it also became non-infective to C. includens, indicating that this NPV isolate could not be utilized to control simultaneously populations of the two species.