Effect of Xylotrechus arvicola (Olivier) (Coleoptera, Cerambycidae) Infestations on Flowering and Harvest in Spanish Vineyards

Abstract

Some high-value vineyards in Spain are increasingly threatened by a xylophagous insect, Xylotrechus arvicola (Olivier), a polyphagous cerambycid that has become a grapevine pest during the last 10 years. Infestations are difficult to detect and control because the larvae excavate large and numerous galleries inside the wood. This study was performed during flowering and harvest time in La Rioja vineyards to evaluate the effects of infestations by X. arvicola on Tempranillo. Results showed that the inflorescence size and number of flowers were considerably reduced and that, during harvest, grape clusters were smaller and looser, weighing on average five times less than those collected from sound branches. Moreover, wine made from grapes on infested branches had significantly lower alcoholic percentage and higher organic acid concentration. These findings show that the damage caused by X. arvicola is severe both in terms of yield and wine composition. Increasing reports of its presence indicate that this serious insect pest be considered in integrated pest management of vineyards.