Control of European grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae) under two different grape trellising systems

Abstract: Lobesia botrana (Denis & Schiffermüller), European grapevine moth, was first discovered in North America in Napa Valley, California, USA in 2009. An eradication program was initiated in the spring of 2010 using insecticides supplemented with pheromone mating disruption. California produces over 83% of wine, raisin and table grapes in the United States with over 350,000 ha under a number of growing conditions and trellising systems. The trellising systems have a major impact on foliage development and airflow within the grape canopy. The foliage development can have an impact on insecticide penetration and fruit cluster coverage. This paper reports on the efficacy of several commonly used insecticides for control of both spring and summer generations of L. botrana on two trellising systems. The two trellising systems were Smart-Henry and Quadrilateral. The Smart-Henry system is a two-tier system that is highly manicured that requires leaf removal and provides maximum sun exposure and excellent airflow. The Quadrilateral system is a four cordon system that is minimally pruned and provides excellent shading but little airflow. All insecticides evaluated provided adequate control regardless of trellising system or generation with spinosad providing the highest control. Mortality was significantly higher with the Smart-Henry compared to the Quadrilateral trellising system in the second generation of L. botrana. There was greater mortality at the first generation as compared to the second generation with both trellising systems. However, there was a greater difference in mortality between the first and second generations with the Quadrilateral compared to the Smart-Henry trellising system.