Seasonal phenology and feeding preference of brown marmorated stink bug, Halyomorpha halys (Heteroptera: Pentatomidae) in vineyards

Halyomorpha halys is an invasive insect pest from Asia having significant impact in numerous crops and fruits.  It is considered as an occasional pest of both wild and cultivated grapes in its native habitat and the pest status has not been thoroughly studied in vineyards. Therefore, population of H. halys was monitored in 2012 and 2013 in different vineyards across Virginia. In 2012 and 2013, four vineyards were selected to study its phenology and distribution pattern within the vineyards. Two blocks were selected in each vineyard, adjacent to the winery and the woods. Three minute timed visual count sampling was done at the border and the middle section. Grapes serve as the early season reproductive host. The spring adults emerge from overwintering sites and move to the vineyards for laying eggs. Higher densities of H. halys was found  in border rows than in middle rows of the vineyard. There was no significant effect of the orientation of a vineyard block. H. halys egg masses were mostly laid in June and July. Based on degree day model, only one generation was found in Virginia vineyards. With the beginning of the veraison stage of grape, the berries start accumulating sugars and the bugs move to the lower horizon (vineyard trail) for feeding. The stink bug density in the late season mainly depends on the availability of the other host plants around vineyards. Since all the growth stages of H. halys were found, grape is a reproductive, developmental and feeding host. A few days after H. halys feeds on grape berries, small necrotic spots develop at the site of stylets insertion. A laboratory study was conducted to determine the varietal preference of H. halys to grapes. H. haly showed preference for the white varieties over red varieties of grapes.