Fruit Flies in Pineapple Plants

by Kristi Waterworth Google
    Pineapple plants enhance the landscape with their stiff, strappy foliage.

    Pineapple plants enhance the landscape with their stiff, strappy foliage.

    Pineapples (Ananas comosus) are favorite landscape plants in U. S. Department of Agriculture plant hardiness zones 10 through 11, but are also moving indoors across the United States. Pineapples are fairly hardy and pest resistant, but are sometimes plagued by curious insects like fruit flies. Depending in whether they are indoors or out, you may be dealing with the household pests known as vinegar flies (primarily Drosophila melanogaster) or the more bothersome spotted wing drosophila (Drosophila suzukii), which feeds primarily outside.

    Fruit Flies

    The term "fruit fly" is applied to any small member of the genus Drosophila that feeds or reproduces on fruit. The most common are the vinegar fly and the spotted wing drosophila, but these tan flies are difficult to distinguish at a glance. Both are about 1/10-inch long with red eyes, but the spotted wing drosophila also bears a single black spot on the back of each wing. Vinegar flies are only attracted to fermenting fruit, but spotted wing drosophila will readily attack healthy fruit, making them a significant problem for fruit growers.


    Vinegar flies are annoying pests, but do little damage to healthy plant tissues. They are attracted to the fermentation of rotting fruits, using them as sites for laying eggs. The larvae soon hatch, feed and spread. Vinegar flies sometimes transmit organisms from fruit to fruit that can cause spoilage, such as yeast and bacteria. In addition, spotted wing drosophila will inject eggs into healthy fruit; the developing larvae causing brown, soft or sunken areas that weep fluid.

    Detecting Breeding Sites

    Detecting the breeding sites of fruit flies is an important step to eliminating them. If your troubled pineapples are outside, locating breeding sites may be difficult or impossible and using sticky traps may be a better way to detect fruit fly activity. Indoor breeding sites, though, can be detected by taping over garbage disposals and drains with clear tape.

    Control Measures

    A variety of methods is used to control fruit flies. Cleaning up fermenting fruit is a good first step, so check your garden or home carefully for fruits that may be past their prime. Most fruit flies can be trapped near breeding sites, using commercial traps or homemade ones containing fermented fruit covered with an inverted funnel. Pyrethrin and spinosad have shown to be effective against fruit flies when applied thoroughly to affected plants and can be used on edible ornamentals like pineapples.

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