Four months after an invasion of Tau fruit flies prompted city officials to place Santa Clarita Valley under quarantine, Southern California has been hit with two new fruit fly infestations. This time, the invading insects are the Queensland fruit fly, which is native to northeastern Australia, and the Mediterranean fruit fly, which is native to sub-Saharan Africa.

After two Queensland fruit flies were detected in Thousand Oaks, an area of 76 square miles was put under quarantine. The region includes parts of Ventura and Los Angeles counties, where a variety of regional crops — including fruits like strawberry, grape, citrus, apricot, fig, avocado, peach, cherry, apple, nectarine, pear, and plum, as well as vegetables like sweet pepper and tomato — are at risk of infestation. This infestation occurs when the female fruit flies lay eggs inside the crops themselves. Once those eggs hatch, maggots bore their way through the crops’ flesh, rendering them unsafe to be consumed.

The Queensland fruit fly infestation is the first of its kind in the western hemisphere, and the Venture County Farm Bureau is worried. “What’s at stake if this fruit fly continues to spread is over $2 billion in economic activity, agri-tourism, 25,000 jobs, and 6,000 indirect jobs,” says the bureau’s CEO, Maureen McGuire.

The organic pesticide Spinosad GF-120 Naturalyte is being used to treat areas affected by the infestation. Residents into the quarantined area have also been asked to double-bag any plant waste before disposing of it in the trash, and to avoid removing fruits and vegetables from their properties.

Earlier this month, a similar infestation occurred in the Los Angeles neighborhood of Leimert Park, where three Mediterranean fruit flies were found in fly traps on fruit trees. According to the USDA’s Animal and Plant Health Inspection Service, these flies are “the most important agricultural pest in the world.” They have infested “fruits, nuts and vegetables, including apple, avocado, bell pepper, citrus, melon, peach, plum and tomato” since their first infestation of the American mainland occurred in Florida back in 1929.

To halt the spread, officials have instituted a 69-mile quarantine, along with the usual double-bag recommendations. More notably, they’re dropping 250,000 sterile male flies per square mile into the affected area on a weekly basis. This is a method of fly birth control, essentially, wherein the sterile males mate with females and produce infertile eggs that don’t produce any offspring.

At FGS, we have a long history of assisting growers in keeping flies and other pests away from their operations. Composting manure, utilizing fly traps, practicing crop rotation, encouraging the presence of natural predators, and applying nematodes are all ways to keep fly infestations under control. To improve your own pest control methods, please give us a call!

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