Parasitoids of blueberry gall midge (Diptera: Cecidomyiidae) in Florida blueberries and potential for biological control

Blueberry gall midge (BGM), Dasineura oxycoccana (Johnson), is a major pest of rabbiteye blueberries, Vaccinium ashei Reade, in the southeastern United States. Larvae feed in developing flower and leaf buds, killing the buds and limiting the blueberry plant’s ability to produce a crop. A survey of parasitic Hymenoptera was conducted to identify potential natural enemies of blueberry gall midge in the blueberry agroecosystem. Yellow sticky traps were hung in blueberry bushes during flower bud development in 2006 and 2009 to monitor parasitoid activity. Emergence traps were also used to monitor parasitoids emerging from the soil. Several families of wasps were recorded and identified as potential natural enemies of BGM. Parasitized midge larvae were also collected from flower buds, and parasitoids were reared to adult for identification. The most common parasitoids reared from midge larvae belonged to the genera Platygaster and Aprostocetus. Parasitized midge larvae were collected from leaf buds in 2009. Thirty-seven percent of BGM larvae from leaf buds were parasitized. Highest parasitism rates were observed in third instar midge larvae (66%) and in larvae located in the outer layers of leaf buds (47%). Parasitic Hymenoptera may play an important role in regulating BGM populations in blueberries. Further research is needed to determine their impact. In addition, conservation biological control should be practiced to avoid disrupting naturally occurring populations of BGM parasitoids.