Acquisition of lethal infection, hypermobility and modified climbing behavior in nucleopolyhedrovirus infected larvae of Anticarsia gemmatalis

Publication date: Available online 12 July 2018Source: Biological ControlAuthor(s): Christian Del-Angel, Rodrigo Lasa, Gabriel Mercado, Luis A. Rodríguez-del-Bosque, Primitivo Caballero, Trevor WilliamsAbstractThe Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) is the basis for viral insecticides in several countries in Latin America. The rate of acquisition of infection and the transmission of the pathogen from infected to healthy conspecifics both influence the efficacy of virus insecticides. By comparing the leaf area consumed by larvae with their stage-specific susceptibility to infection, we estimated that fourth instars were approximately twice as likely to acquire infection as second or third instars. Greenhouse trials indicated that 63% of third instars became infected within 1 h of exposure to soya plants treated with 1.5 x 107 occlusion bodies (OB)/m2 obtained from mixtures of local AgMNPV isolates, as did 90% of larvae sampled at 24 h. Acquisition of lethal infection was slower in field trials performed in the soya-growing Huastecas region of Mexico. Virus-induced mortality varied from 43 to 79% in natural infestations of larvae sampled at 72 h post-application depending on the dose of unformulated OBs applied with wetting agent, although the majority of larvae had already acquired a lethal infection at 24 h post-application. Spray application volume (200 or 400 l/ha) did not significantly affect the prevalence of infection at 1 h post-application. In...
Source: Biological Control - Category: Biology Source Type: research