Susceptibility of Lobesia botrana (Lepidoptera: Tortricidae) to chlorantraniliprole in the Emilia Romagna Region of Northeast Italy

Abstract

The European grapevine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), is regarded as the most important insect pest of wine grapes in Europe. If not properly controlled, it can cause significant direct and indirect yield losses due to secondary infections of grape berries by Botrytis cinerea. For these reasons, it is important to preserve the activity of insecticides used against this pest, as the number of insecticidal mode of actions available to control Lepidoptera species on wine grapes in Europe is limited. Following a report of suboptimal control of L. botrana after field applications of chlorantraniliprole-containing products, an extensive monitoring program was conducted in the Emilia Romagna Region of North East Italy to determine L. botrana susceptibility to chlorantraniliprole. This study consisted of 11 bioassays conducted with chlorantraniliprole on L. botrana populations collected in the Emilia Romagna Region in 2014-2016, 5-7 years after its introduction into the market. Bioassay results were compared to results previously obtained from the chlorantraniliprole pre-comercialization baseline susceptibility survey conducted from 2007 to 2011. The Lethal Concentration values obtained for field populations of L. botrana in this study are comparable to those reported for the pre-comercialization susceptibility baseline. We demonstrate that there is no significant change in L. botrana susceptibility to chlorantraniliprole in the Emilia Romagna Region. Emphasis should be given to implement appropriate insecticide resistance management strategies, including nonchemical agronomic practices and biological control methods, to preserve effective insecticides like chlorantraniliprole for future use in controlling the European grapevine moth.

Keywords: Lobesia botrana; chlorantraniliprole; diamide insecticides.