Attract and reward: a novel approach to enhancing biological control of crop pests

Synergistic attract and reward' effects were demonstrated in broccoli with Scelionidae being increased in MeSA treatments with reward. Attract' and reward' alone increased several beneficial hymenoptera and predators in all three tested crops. In sweet-corn, increases in natural enemy numbers were complemented by effects at the first and second trophic level. A subsequent experiment tested the attract and reward' approach on a larger scale in three different vineyards. Various hymenoptera, predators and thrips responded to the same HIPVs and reward in each of the three vineyards, identifying that attract' and reward' can lead to the same results across different sites. To gain an understanding of the chemical ecology mechanisms that were likely to have been involved in the field experiments, a laboratory study was conducted. Undamaged, pest-free broccoli plants were treated with MeSA (1.0%) in Synertrol® (v/v). Solid phase micro-extraction (SPME) was used for headspace volatile collection. Findings demonstrate that MeSA in Synertrol® may be an elicitor that changes the profile of volatile compounds emitted by treated broccoli plants. MeSA was only detectable two hours post treatment, suggesting that arthropods may be directly attracted to the HIPVs for only one day post treatment.