Spotted Wing Drosophila
Several calls have come in regarding the spotted wing drosophila (SWD). The SWD is an invasive insect pest native to Asia and was first confirmed in Minnesota in 2012. The SWD is a pest of thin-skinned soft fruit such as raspberry, blackberry, blueberry, strawberry, grape, plum, and cherry.
The SWD is similar in appearance to common fruit flies found near overripe fruit. They are 1/8 to 1/12 inch long with yellowish-brown coloration and red eyes. Males are easy to identify because they have a dark spot along the first vein near the tip of each wing (fig. 1). Females have clear wings, like males, but lack the dark spot near the wing tips making them difficult to identify (fig. 2). Females insert eggs into ripe or ripening fruit. Upon hatching, larvae feed on the fruit causing brown sunken areas (fig. 3). Feeding damage also makes fruit more susceptible to infestation by other insects, fungi, and bacteria. After feeding, larvae leave the fruit to pupate and later emerge as adults.
Under optimum conditions SWD can complete its life cycle in as little as 7 – 10 days. Multiple generations of SWD can occur in a year with populations building throughout the summer. If you find SWD in your garden, it is necessary to protect susceptible crops with an insecticide application. Several insecticides are available. Be sure that the specific insecticide product you wish to use is labeled for the fruit you want to treat. Also, pay close attention to the preharvest interval (PHI) of the insecticide. If you are treating raspberry, try to find an insecticide with a short PHI such as one or two days. More information about SWD along with insecticide recommendations can be found at: http://z.umn.edu/drosophila
From last weeks question on the air about indoor perennial plantings:
I have been thinking about the question posed last week regarding perennials that would make good houseplants. No perennials come to mind although there could be some out there. What did come to mind were annuals. When I was young, both of my grandmothers grew angel wing begonias as houseplants. There are several angel wing type begonias that people grow as annuals that could be brought indoors in the fall that would make nice houseplants. Geraniums are another annual that can make a good houseplant. Another annual that I used to keep indoors when I was younger was impatiens. They were not the best houseplant but they would stay alive until I replanted them outdoors in the spring.
If you have questions about SWD in your garden please call me at the University of Minnesota Extension office, Clay County at 218-299-7338, 1-800-299-5020 or by email nels1657@umn.edu. Check out our website: https://local.extension.umn.edu/local/clay Sources: Suzanne Wold-Burkness, University of Minnesota, Department of Entomology and Jeffrey Hahn, University of Minnesota Extension Entomologist.
