A year ago in August, the spotted wing drosophila (Drosophila suzukii) was discovered in the strawberry producing area of Hillsborough County after having been known about one year in California and for less time in Washington. Since arriving in Florida, the fly has expanded its range to include at least the Carolinas, Michigan, Kentucky, and Louisiana. It is probably infesting most states among those, but has not been detected by folks that know its damage. The fly also is expanding its range in Europe. No commercially significant damage was reported from Florida berries during the winter and spring 2010 strawberry and blueberry seasons, probably a blessing of the record-breaking cold weather we experienced then.
This fly that originated in the Orient resembles the common Drosophila spp. flies that accumulate on over-ripe bananas, berries left without refrigeration, rotting fallen citrus, and other fruit beginning to spoil. In fact, both are small, have prominent red eyes and, indeed, are closely related.Wing tips of spotted wing drosophila males contain a dark spot that is lacking in our common drosophilids.
Female spotted wing drosophilas possess serrations on their egg laying organ that can cut soft surfaces of sound fruit to lay eggs inside. Common drosophilid flies are without that modified ovipositor. Spotted wing drosophila eggs that hatch inside fruit become white maggots, which can soften and ruin fruit in the field or can accompany harvested fruit undiscovered until the fruit are in consumers’ hands.
This group of small flies often is called the pomace, vinegar, or fruit flies, but “fruit flies” in this case is confusing since that common name applies to larger flies, the Tephritidae, often problematic and reported in the news media when outbreaks occur. Tephritids include banded winged flies such as Mediterranean fruit fly, Caribbean fruit fly, Oriental fruit fly, Mexican fruit fly, and others. Drosophilid flies are not closely related to tephritid flies and management of the two groups can be vastly different. For instance, rare outbreaks of Mediterranean fruit flies in Florida are managed in part with mass releases of sterilized male Mediterranean fruit flies. This technique has not been developed for drosophilids and is impractical to consider in most cases.
On The Fly
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