Effect of Host Plant Resistance on Thrips Development

Abstract

Thrips (Frankliniella occidentalis and Thrips parvispinus) are a major pest in pepper cultivation. Control of thrips is difficult because of their polyphagous and cryptic behaviour as well as their increasing resistance to many insecticides. Host plant resistance is therefore urgently needed. We characterized 32 accessions from 4 pepper species for resistance to thrips, resulting in the identification of 9 accessions with contrasting levels of resistance (highly resistant, medium resistant and susceptible). Adult and pre-adult survival, developmental time and reproduction rate were assessed. Our results show that resistance had no effect on adult survival, but that oviposition rate and larval mortality are significantly affected. In the resistant accessions the development of thrips larvae was blocked. Using gas chromatography – mass spectrometry, we could identify several compounds that correlate with the level of resistance to thrips. Some of them have already been shown to have an effect on insects. Also, some specific secondary metabolites were shown to be induced by thrips infestation.