Novel strategies for the biocontrol of noctuid pests (Lepidoptera) based on improving ascovirus infectivity using Bacillus thuringiensis

This article is protected by copyright. All rights reservedAbstractIdentifying novel biocontrol agents and developing new strategies are urgent goals in insect pest biocontrol. Ascoviruses are potential competent insect viruses that may be developed into bioinsecticides, but this aim is impeded by their poor oral infectivity. To improve theper os infectivity of ascovirus,Bacillus thuringiensis kurstaki (Btk) was employed as a helper to damage the midgut of lepidopteran larvae (Helicoverpa armigera,Mythimna separata,Spodoptera frugiperda, andS. litura) in formulations withHeliothis virescens ascovirus isolates (HvAV ‐3h and HvAV‐3j).Btk and ascovirus mixtures (Btk/HvAV ‐3h andBtk/HvAV ‐3j) were fed to insect larvae (third instar). With the exception ofS. frugiperda larvae, which exhibited low mortality after ingestingBtk, the larvae of the other tested species showed three types of response to feeding on the formulas: type I, the tested larvae (H. armigera) were killed byBtk infection so quickly that insufficient time and resources remained for ascoviral invasion; type II, bothBtk and the ascovirus were depleted by their competition, such that neither was successfully released or colonized the tissue; type III,Btk was eliminated by the ascovirus, and the ascovirus achieved systemic infection in the tested larvae. The feeding ofBtk/ascovirus formulas led to a great reduction in larval diet consumption and resulted in a significant decrease in the emergence rate ofH. arm...
Source: Insect Science - Category: Biology Authors: Tags: ORIGINAL ARTICLE Source Type: research
More News: Biology | Diets | Nutrition | Science