By Natalie Willis, Reporter, Valley Ag Voice
Invasive pests swarmed California agriculture last year as increased rainfall created ideal conditions for tiny creatures to make a large impact on the agricultural industry. Fruit flies have remained a prominent issue for fruit growers — specifically Tau, Oriental, Mediterranean, and Queensland fruit flies which each triggered quarantines throughout California.
The California Department of Food and Agriculture lifted the Tau fruit fly Los Angeles County quarantine in June which covered 110 square miles. The quarantine was put in place in July 2024 after the invasive pests were first detected, marking the first time the Tau fruit fly initiated a quarantine in the Western Hemisphere.
In a press release, Victoria Hornbaker, director of CDFA’s Plant Health and Pest Prevention Services Division explained that the eradication efforts were successful for one of the largest statewide invasive fruit fly populations in California in several years.
“The lifting of this quarantine proves that our efforts are working, and the responsiveness and cooperation of residents across California and our partners is critical to that success,” Hornbaker said.
The quarantine prevented the harvesting or movement of over 300 varieties of crops without meeting strict treatment standards. While the Tau fruit fly has been successfully eradicated, there are still three active quarantines for the Oriental, Mediterranean, and Queensland fruit flies.
While the quarantine in Contra Costa County was lifted in July, Riverside County and San Bernardino County are under active quarantine for the Oriental fruit fly, a pest that poses a threat to several crops in California including pears, plums, cherries, peaches, apricots, figs, citrus, tomatoes, and avocados.
According to the CDFA, the OFF would amount to up to $176 million in crop losses, additional pesticide use, and quarantine requirements. The Oriental fruit fly has been introduced into California several times by the movement of infested fruits and vegetables into the state, and while infestations have been found in the state, they are usually successfully eradicated.
The Mediterranean fruit fly also triggered a quarantine in LA County in 2023 as the presence of an established population would cause a severe economic impact through the restriction or prohibition on fresh fruit exports both domestically and internationally, CDFA explained.
The Mediterranean fruit fly has one of the widest host ranges of any pest fruit fly and is considered the most important agricultural pest in the world. According to the CDFA, it has been recorded infesting over 250 cultivated and wild fruits.
The CDFA has a Preventative Release Program to control Medflies, which has reduced infestations in the Los Angeles area by about 93%.
Another active quarantine for the Queensland fruit fly is in place in LA and Ventura Counties. The quarantines went into place in November 2023 to prevent its spread and protect the state’s agriculture industry.
The exotic insect originated in Australia but the first detection in California occurred in 1985 in San Diego County. According to CDFA, the QFF feeds on several types of fruits and vegetables, including pome and stone fruits, citrus, dates, avocados, and many vegetables, particularly melons and tomatoes.
PREVENTING THE SPREAD
To help prevent future introductions of invasive species, the CDFA requested that residents cooperate with agricultural officials by allowing them access to gardens to place traps, inspect plants, conduct necessary treatments, or remove potentially infested produce.
As temperatures rise and vacationers ramp up their travel plans throughout the summer, agriculture officials are urging residents to refrain from bringing back potentially infested produce from their trips.
Residents can determine if their property is located within an active quarantine area by visiting CAFruitFly.com. Residents should inspect their gardens for signs of invasive fruit flies or maggots and report any findings to the CDFA at (800) 491-1899 or their local county agricultural commissioner’s office.
