CONTROL OF EUROPEAN GRAPEVINE MOTH IN WINE GRAPES, 2012

This study was designed to evaluate reduced-risk insecticides for EGVM control in wine grapes. The study was conducted in mature ‘Syrah’ grape vines in two commercial vineyards near Acampo and Escalon, CA. The Acampo vineyard was planted on a 2.7 m by 1.8 m (row by vine) spacing and used a Smart-Henry two-tier trellising system that was highly manicured with excellent sun exposure and airflow. The Escalon vineyard was 3.4 m by 2.1 m (row by vine) spacing and used a quadrilateral trellising system that provided shading with minimal pruning. Six treatments were replicated four times in a RCB design in each vineyard. Each replicate was six vines long with a buffer vine between treatments and a buffer row between blocks. Treatments were applied by a hand-operated backpack sprayer delivering a finished spray volume of 467.7 liters/ha. Treatments were applied in each vineyard on 21 May and 25 Jun to correspond with the grape development stage estimated to coincide with first and second generation EGVM larval emergence. Two grape clusters per replicate were collected from each vineyard at 1, 4, 7 and 14 DAT from the center two vines and placed in a thrips extractor for ten minutes. Upon removal from the thrips extractor, the stem was placed in a microcentrifuge vial of water to maintain viability and transported to the UC Davis contained research facility (CRF) to be exposed to neonate larvae. Ten neonate larvae were placed on each cluster. Larvae were obtained from a colony in the CRF and were less than 12 h when transferred. After four days of exposure, clusters were examined and larvae scored for mortality. Moribund larvae were scored as alive. Due to high mortality, two dead larvae from each cluster were disregarded, reducing the maximum number of larvae recovered from each cluster to eight. Data were analyzed using ANOVA, means were separated using Fisher’s protected LSD (P ≤ 0.05).