Biological Control of the Mexican Fruit Fly

Parasitoids

• Parasitoids are parasitic insects that attack other insects. The list of parasitoids used on the Mexican fruit fly is exhaustive. A few listed by the U.S. Department of Agriculture include Opius cereus, Bracanastrepha anastrephae, Ganaspis carvalhoi and Aceratomeuronyia indica. Most parasitoids attack the flies during the larval or pupal stages. Faculty at the University of California, Riverside say that some of the parasitoids used on the Mediterranean fruit fly have also shown some promise against the Mexican fruit fly. The downside: parasitoids can be difficult to rear, and availability may be limited.

Predators

• The USDA lists Homaeotarsus (Rove beetle) and Belomicjis rufipennis (Staphylinid beetle) as predators of the Mexican fruit fly along with the mite, Acari. The USDA also lists the white-footed mouse and the brush mouse as predators that feed on the fly’s pupae. “Psyche: A Journal of Entomology” reports that ants, in the presence of dry soils, effectively control the Mexican fruit fly as well. In one study, ants removed 93 percent of the larvae in 10 minutes. Should you use predators in your yard or orchard, make sure they don’t become pests themselves.

Pathogens

• Bacteria and fungi have also proven effective. The USDA lists Bacilius thuringensis as one bacterium for combating the Mexican fruit fly. This gram-positive, spore-forming bacterium releases an exotoxin that kills the flies. Flies are fed the bacteria either as larvae or adults. Fungi in the form of Beauvenia hassiana and Metarhizium anisopiliae can also be used. Consult your local extension agency for the best sources for these and other biological controls.

Natural Alternatives

• Other ways of naturally dealing with Mexican fruit flies do exist. Remember fruit flies are attracted to garbage, especially rotting or overripe fruit. Securing trashcan lids and refrigerating ripe fruit helps to prevent outbreaks within the home. Gardening expert and educator Andrew Lopez recommends using 1 tablespoon of natural soap and 1 tablespoon tobacco sauce in a gallon of water to spray in places where flies lay eggs. He also recommends using diatomaceous earth on cat, dog and horse feed.