Evaluating the potential impact of Halyomorpha halys on grape production in the Finger Lakes

Our study aims to determine how Halyomorpha halys will affect grape production if the invasive insect becomes well established in the Finger Lakes.  We measured the impact of increasing density, gender, and life stage of H. halys on Concord and Chardonnay grapevines.  We confined insects on a single grape cluster using a fine mesh bag, which we replicated five times each for Concord and Chardonnay.  Each replicate consisted of the following treatments: a bag lacking insects; 2^nd instar nymphs in densities of 5, 10, and 20; adult females in densities of 1, 2, and 5; and adult males in densities of 1, 2, and 5. The insects remained caged on the clusters for 2 weeks during the period of fruit set, after which damaged and undamaged berries were enumerated.  At this point, we found a strong positive correlation between density and both number and percentage of berries damaged for both nymphs and adults.  After this data was collected the bags were returned to the clusters until harvest, at which point clusters were removed from the vines, damaged and undamaged berries were once again counted, and berries were massed.  Density of insects was found to decrease weight per cluster and increase the proportion of damaged berries.  The proportion of damaged berries was also found to be higher as a result of female feeding than male feeding.  This study establishes important groundwork for developing control thresholds for H. halys in Finger Lake vineyards.