Evaluation of traps for monitoring blueberry gall midge (Dasineura oxycoccana Johnson) and using SADIE analysis to model midge and parasitoid distribution in rabbiteye blueberries

Blueberry gall midge (BGM), Dasineura oxycoccana Johnson, larvae develop in blueberry leaf and flower buds. As much as 80% of a rabbiteye blueberry planting can be injured by BGM activity. Emergence and panel traps are both effective monitoring tools for BGM, but no comparisons between them have been made. Surveys for natural enemies conducted in north-central Florida from 2007 to 2010 found numerous platygastrids and eulophids active in blueberry plantings. The objectives of this study were to 1) compare the effectiveness of emergence and panel traps for monitoring BGM and 2) to model the distribution of BGM and its parasitoids in a rabbiteye blueberry field. Experiments were conducted at an organic rabbiteye blueberry farm in Gainesville, FL. Emergence traps, panel traps, and modified panel traps were compared in a RCBD with 4 replicates at 2 field sites. Bud samples were also collected to determine how well the traps predicted larval numbers. To model the distribution of BGM and its parasitoids, a grid of 25 sample points was setup. Emergence and yellow sticky traps were used to monitor BGM and parasitoid adults, respectively. Bud samples were collected to monitor BGM and parasitoid larvae. In field 1, where the BGM population was low, emergence traps performed better than both panel traps. In contrast, emergence and panel traps performed equally well, and better than the modified panel trap, in field 2, where the BGM population was higher. After the first sampling date, BGM and parasitoid populations were randomly distributed throughout the field.