Notes on Blueberry Insects: Blueberry maggot
Blueberry maggot is a regulated pest. The federal Plant Protection Act and Regulations place movement restrictions on blueberry fruit, plants, soil and containers from areas known to be infested with blueberry maggot. These laws exist to prevent the spread of this pest from infested areas, such as Nova Scotia, New Brunswick, Prince Edward Island, Maine, New York, Michigan, to non-infested areas, such as Ontario, Quebec and B.C. All infestations of blueberry maggot must be reported to the Canadian Food Inspection Agency.
The adult blueberry maggot is a fly that is slightly smaller than a housefly. It has a grey-black body with a white spot and distinct dark banding on its wings (see Figure 1). Wing patterns of apple maggot and other related species. The immature stage is a white larva that infests blueberry fruit (See Table 1).
Period of activity
In early July, as the first berries are turning blue, adult flies begin to emerge from pupae in the soil. Emergence and adult activity continues into August. Adult flies lay eggs on developing blueberry fruit and larvae develop inside the fruit. Infested fruit may ripen and soften prematurely. Mature larvae emerge from dropped fruit, then pupate and overwinter in the soil beneath the bushes.
Monitoring and thresholds
Monitor for blueberry maggot flies using yellow sticky traps baited with ammonium acetate. These traps are also used for apple maggot. Place traps in the top 1/3 of the bush, by mid-June, on the perimeter of commercial fields. If abandoned or wild blueberries are nearby, place traps just outside of commercial fields. Clear plant foliage away from the trap so it is plainly visible. See Pest Monitoring Equipment Suppliers on the OMAFRA website.
Insecticides and timings for blueberry maggot control are listed in the OMAFRA Publication 360 Blueberry Calendar.
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