Blueberry Gall Midge Suggested Controls

Blueberry gall midge (Dasineura oxycoccana)is a significant insect pest of blueberries in Florida. Adults only live for 2-3 days, and lay their eggs in floral and leaf buds as the bud scales begin to separate, typically during winter months in Florida. The larvae feed on developing floral and leaf bud tissues, resulting in bud damage, abortion, or death, with reduced or no bloom from affected buds (Figure 1). 


Figure 1. Blueberry gall midge larvae in floral bud

Credits: O. Liburd, UF/IFAS


Suggested management plans for gall midge on southern highbush blueberry in Florida include monitoring and spray applications of recommended insecticides. Monitoring can be performed by using bucket traps (essentially an inverted five-gallon bucket with a plexiglass panel in place of the bottom) or sticky panels and then determining whether any adult gall midge are present in the traps (Figure 2). Recommended insecticides can then be applied when there are two or more adults in a trap, to kill the adults before the females begin to lay eggs in the buds. However, it can be difficult for those without training to differentiate between gall midge and similar species that do not damage blueberries. Another monitoring method is to cut blueberry canes with floral and leaf buds and put them in a Ziploc bag at room temperature for 10 -14 days. If gall midge larvae are present, they will exit the buds and be visible inside the bag, typically with an orange color characteristic of mature larvae (Figure 3). However, at this point the larvae are already present and feeding in the floral buds.


Figure 2. Adult blueberry gall midge

Credits: O. Liburd, UF/IFAS


Figure 3. Blueberry gall midge larvae

Credits: O. Liburd, UF/IFAS


If monitoring for adults is not performed, then preventative sprays may be applied. The first application should be made right before bud break. In recent field trials conducted by Dr. Oscar Liburd and his lab, Movento® (spirotetramat) and Exirel® (cyazypyr) were the most effective insecticide treatments in reducing population of blueberry gall midge. Other products with some level of effectiveness are Malathion, Delegate®, Admire Pro®, Apta®, Assail®, and Sivanto®. Movento® should provide up to 14 days of residual activity. Additional applications of these insecticides can be made on a rotational basis at 7-10 day intervals if gall midge populations remain high. As with all pesticides, label instructions including reapplication intervals, maximum number of applications in a season, and warnings for when pollinators are present should be closely followed. For a more detailed discussion of this topic see UF EDIS Publication ENY-997, Blueberry Gall Midge on Southern Highbush Blueberry in Florida (https://edis.ifas.ufl.edu/in1239).


by DR. OSCAR LIBURD, UF Professor and Program Leader, Fruit and Vegetable Entomology,
and DOUG PHILLIPS, UF Blueberry Extension Coordinator

 
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