Field evaluation of the 'attract and reward' biological control approach in vineyards.

Herbivore plant damage induces emissions of semiochemicals termed herbivore-induced plant volatiles (HIPVs). These volatile cues can attract the natural enemies of the attacking herbivores and protect the plant from further damage. Synthetic HIPV application to various crops has also been shown to attract natural enemies. In the present study, nectar plant rewards were combined with HIPVs in an 'attract and reward' approach. This combination might attract natural enemies into treated crops and provide them with food and shelter to maximise their survival and residency leading to increased parasitism and lower pest abundance. Trap catches of predators and scelionid parasitoids in treated grapevines were increased by methyl salicylate (MeSA) and methyl anthranilate (MeA) for 1 day and up to 5 days, respectively. The number of herbivorous thrips was also increased for up to 3 days post-treatment. Buckwheat ( Fagopyrum esculentum) reward increased catches of eulophid parasitoids and thrips over the 28-day experiment. These results suggest that 'attract' and 'reward' can separately enhance local abundance of natural enemies but further work is required to fully realise the potential for synergistic effects. [ABSTRACT FROM AUTHOR]