Effects of a feeding stimulant on the efficacy of a (Bacillus thuringiensis) insecticide against the lightbrown apple moth, (Epiphyas postvittana), and the Diamondback moth, (Plutella xylostella) : a dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Horticultural Science (Honours) at Lincoln University

Abstract

Feeding stimulants have been used successfully to improve the efficacy of stomach acting Bacillus thuringiensis (Bt) insecticides against some lepidopterous pests. This improves the cost effectiveness of these environmentally soft pesticides, and hence makes them more acceptable as replacements for broad spectrum synthetic formulations.

Bioassays comparing the rate responses of Lightbrown apple moth, (Epiphyas postvittana), and Diamondback moth (Plutella xylostella) to a Bt insecticide alone and with a feeding stimulant were carried out. Results did not indicate any improvement in efficacy at most rates of Bt. Some low rates of Bt did show improved efficacy soon after application, but this advantage was lost within 36 hours. Choice tests did not show any increase in larval incidence on treated foliage with the addition of the feeding stimulant.

All results obtained in this study were subject to large variation, and strict conclusions cannot be drawn from this study.