Leafroller-induced phenylacetonitrile and acetic acid attract adult Lobesia botrana in European vineyards

Abstract

We recently identified unique caterpillar-induced plant volatile compounds emitted from apple leaves infested with the larvae of various leafroller species. In subsequent field tests, binary blends of phenylacetonitrile+acetic acid and 2-phenylethanol+acetic acid were found to be attractive to a range of tortricid leafroller species (Tortricidae: Tortricinae) in both the Southern and Northern Hemispheres. In this work, the caterpillar-induced plant volatiles from the apple-leafroller system were tested in two vineyards in Spain and Hungary for their attractiveness to the grape frugivore Lobesia botrana (Tortricidae: Olethreutinae). As seen for Tortricinae species, a binary blend of phenylacetonitrile+acetic acid attracted significantly more male and female L. botrana to traps than acetic acid or blank lures. Traps baited with other caterpillar-induced plant volatile compounds (benzyl alcohol, 2-phenylethanol, indole, and (E)-nerolidol, each as a binary blend with acetic acid) did not catch significantly more moths than traps containing acetic acid alone. The catches of male and female moths support an optimistic future for new products in female tortricid surveillance and control that are based on combinations of kairomone compounds released from larval-damaged foliage.

This work was supported by the New Zealand Institute for Plant & Food Research by Core Funding (Viticulture Sector and Better Border Biosecurity, www.b3nz.org) from the Ministry of Business Innovation and Employment. Thanks also to the field workers (Byrappa Ammagarahalli, Pedro Gomes, and Isabel Romero), the field owner (Josep Giu), and the plant-protection specialist (Rosa Bisa) who worked with us in Spain. Special thanks to Péter Rózsahegyi for his support in choosing the proper experimental site in Hungary.