- Author: Belinda Messenger-Sikes
The invasive pest spotlight focuses on emerging or potential invasive pests in California. In this issue we are covering the Oriental fruit fly.
Oriental Fruit Fly Facts
The Oriental fruit fly (OFF) is an invasive pest that attacks over 230 crops including citrus and other fruits, nuts, vegetables, and berries. The short life cycle of the OFF allows rapid development of serious outbreaks, which can cause severe economic losses. Heavy infestations can cause complete losses of crops. Fruit that has been attacked may be unfit to eat as larvae tunnel through the flesh as they feed. Fungi and bacteria enter, leaving the interior of the fruit a rotten mass. Infested fruit does not always look damaged from the outside but may take on a brown, mottled appearance as the maggots feed.
The adult OFF is slightly larger than a housefly, around 1/3 inch (8mm) in length. The body color is often bright yellow with a dark "T" shaped marking on the abdomen. The wings are clear. The female has a pointed slender ovipositor to deposit eggs under the skin of host fruit. A single female can lay more than 1,000 eggs in her lifetime. The fly can infest new areas very quickly because it is a strong flyer and can travel 30 miles in search of food and sites to lay eggs.
What Can You Do?
The Oriental fruit fly is a major pest of agriculture in Hawaii and efforts to prevent its establishment into California are ongoing. Areas where OFF have been detected are under quarantine. If you are in a quarantine area, you can help by controlling the movement of your homegrown fruit off your property and by disposing of infected fruit in the garbage, not in green waste or compost. If you suspect you've found OFF, notify your County Agricultural Commissioner's office or call the California Department of Food and Agriculture (CDFA) Pest Hotline at 1-800-491-1899.
/h2>/h2>- Author: Michael Hsu
QFF quarantine in LA, Ventura counties among seven fruit fly quarantines statewide
Residents in multiple Southern California and Northern California counties should not move homegrown fruits and vegetables from their properties to help contain several species of fruit fly that can destroy crops and impact the livelihoods of local farmers.
With sharing and gifting of food integral to the holiday season, the California Department of Food and Agriculture is reminding people to heed the seven active fruit fly quarantines aimed at controlling the Mediterranean fruit fly, Oriental fruit fly, Tau fly and Queensland fruit fly. The links below describe quarantine zone boundaries:
- Mediterranean fruit fly: Los Angeles County, Leimert Park Area
- Oriental fruit fly: San Bernardino and Riverside Counties, Redlands and Yucaipa Areas
- Oriental fruit fly: Sacramento County, Rancho Cordova Area
- Oriental fruit fly: Contra Costa County, Brentwood Area
- Oriental fruit fly: Santa Clara County, Santa Clara Area
- Tau fly: Los Angeles County – Stevenson Ranch, Valencia, Santa Clarita Areas
- Queensland fruit fly: Ventura and Los Angeles Counties, Thousand Oaks Area
People within these zones should consume or process (i.e., juice, freeze or cook) their homegrown fruits and vegetables at the place of origin and not move them off their property. Uneaten produce should be double-bagged in plastic bags and disposed of in the landfill bin – not compost or green waste.
Queensland fruit fly threatens California citrus, other crops
The Queensland fruit fly (Bactrocera tryoni) quarantine is the first of its kind in the U.S. Although QFF was first seen in California in 1985, the recent detection of two adult males triggered the unprecedented quarantine action by USDA's Animal and Plant Health Inspection Service and CDFA.
“This pest has earned a bad reputation for wreaking havoc on fruit production in Australia, where it is native,” said Hamutahl Cohen, University of California Cooperative Extension entomology advisor for Ventura County. “Adult flies lay their eggs in fruit, and the eggs hatch into larvae that then feed on the fruit, causing damage.”
And while females of other fruit fly species live for only two or three months, QFF females are unique in that they can live up to a year, according to Cohen.
“Once QFF populations take root, they're challenging to manage because females can each lay up to 100 eggs per day,” Cohen said.
In addition to being highly adaptable to a variety of environmental conditions, QFF has more than 170 host plants – including a wide range of California commodities such as citrus, grape, strawberry, fig, avocado, apricot, peach, cherry, nectarine, plum, pear, apple, tomato and sweet pepper.
The threat to citrus is especially concerning, as Southern California growers continue to grapple with the specter of spreading huanglongbing (HLB) disease, which kills citrus trees. Cohen said residents of citrus-growing regions can do their part to help their neighbors and local economy by respecting quarantine restrictions.
“Growers are already dealing with other invasive species like Asian citrus psyllid [vector of HLB pathogen], so we as homeowners need to prevent the spread of fruit flies to reduce the burden on them,” she explained.
While a spike this year in the detections of multiple fruit fly species was likely caused by a host of factors, Cohen speculates that increased post-pandemic travel is helping to move the flies. And with holiday travel in full swing, she said it's important to practice “Don't Pack a Pest” principles.
“Invasive species often hitchhike on fruits and vegetables brought into California by travelers – that's why we often first find invasive species in urban and suburban backyards, and not on farms,” Cohen said. “Travelers entering the U.S. can visit dontpackapest.com to learn about which products they can and cannot bring back with them.”
To report a suspected infestation of fruit fly larvae in homegrown produce, call the CDFA pest hotline at 1-800-491-1899. Growers with questions and concerns are urged to contact their local agricultural commissioner's office.
/h3>/h3>- Author: Michael Hsu
QFF quarantine in LA, Ventura counties among seven fruit fly quarantines statewide
Residents in multiple Southern California and Northern California counties should not move homegrown fruits and vegetables from their properties to help contain several species of fruit fly that can destroy crops and impact the livelihoods of local farmers.
With sharing and gifting of food integral to the holiday season, the California Department of Food and Agriculture is reminding people to heed the seven active fruit fly quarantines aimed at controlling the Mediterranean fruit fly, Oriental fruit fly, Tau fly and Queensland fruit fly. The links below describe quarantine zone boundaries:
- Mediterranean fruit fly: Los Angeles County, Leimert Park Area
- Oriental fruit fly: San Bernardino and Riverside Counties, Redlands and Yucaipa Areas
- Oriental fruit fly: Sacramento County, Rancho Cordova Area
- Oriental fruit fly: Contra Costa County, Brentwood Area
- Oriental fruit fly: Santa Clara County, Santa Clara Area
- Tau fly: Los Angeles County – Stevenson Ranch, Valencia, Santa Clarita Areas
- Queensland fruit fly: Ventura and Los Angeles Counties, Thousand Oaks Area
People within these zones should consume or process (i.e., juice, freeze or cook) their homegrown fruits and vegetables at the place of origin and not move them off their property. Uneaten produce should be double-bagged in plastic bags and disposed of in the landfill bin – not compost or green waste.
Queensland fruit fly threatens California citrus, other crops
The Queensland fruit fly (Bactrocera tryoni) quarantine is the first of its kind in the U.S. Although QFF was first seen in California in 1985, the recent detection of two adult males triggered the unprecedented quarantine action by USDA's Animal and Plant Health Inspection Service and CDFA.
“This pest has earned a bad reputation for wreaking havoc on fruit production in Australia, where it is native,” said Hamutahl Cohen, University of California Cooperative Extension entomology advisor for Ventura County. “Adult flies lay their eggs in fruit, and the eggs hatch into larvae that then feed on the fruit, causing damage.”
And while females of other fruit fly species live for only two or three months, QFF females are unique in that they can live up to a year, according to Cohen.
“Once QFF populations take root, they're challenging to manage because females can each lay up to 100 eggs per day,” Cohen said.
In addition to being highly adaptable to a variety of environmental conditions, QFF has more than 170 host plants – including a wide range of California commodities such as citrus, grape, strawberry, fig, avocado, apricot, peach, cherry, nectarine, plum, pear, apple, tomato and sweet pepper.
The threat to citrus is especially concerning, as Southern California growers continue to grapple with the specter of spreading huanglongbing (HLB) disease, which kills citrus trees. Cohen said residents of citrus-growing regions can do their part to help their neighbors and local economy by respecting quarantine restrictions.
“Growers are already dealing with other invasive species like Asian citrus psyllid [vector of HLB pathogen], so we as homeowners need to prevent the spread of fruit flies to reduce the burden on them,” she explained.
While a spike this year in the detections of multiple fruit fly species was likely caused by a host of factors, Cohen speculates that increased post-pandemic travel is helping to move the flies. And with holiday travel in full swing, she said it's important to practice “Don't Pack a Pest” principles.
“Invasive species often hitchhike on fruits and vegetables brought into California by travelers – that's why we often first find invasive species in urban and suburban backyards, and not on farms,” Cohen said. “Travelers entering the U.S. can visit dontpackapest.com to learn about which products they can and cannot bring back with them.”
To report a suspected infestation of fruit fly larvae in homegrown produce, call the CDFA pest hotline at 1-800-491-1899. Growers with questions and concerns are urged to contact their local agricultural commissioner's office.
/h3>/h3>- Author: Kamyar Aram
(Este post está disponible en español)
In early September 2023, nearly the entire growing area around the city of Brentwood was put under a quarantine by the California Department of Food and Agriculture (CDFA) (see current included area). This severe regulatory measure was triggered by numerous finds of the oriental fruit fly by Contra Costa County's Department of Agriculture during routine monitoring. This exotic pest (meaning that it is not established in the U.S.) is on the United States Department of Agriculture's (USDA) list of non-native species that pose the greatest potential threat to agriculture and the environment. Given the strict and potentially costly treatment and record-keeping requirements in the middle of a busy harvest season, and, for some in the growing community, outright losses, many are likely wondering why this pest is so great a concern.
What is the Oriental fruit fly and why is it a threat to agriculture?
These include most fruit crops grown in the Brentwood area and in California, in general, including most pome and stone fruit (apple, apricot, cherry, peach and nectarine, pear and plum), most citrus fruit, grape and walnut, as well as specialty market fruits such as avocado, fig, persimmon and pomegranate, to name a few.
Vegetable fruits are also susceptible, including bell pepper, cucumbers, melons and squashes and tomatoes. (Curiously, almonds, olives, strawberries and pumpkins* are not considered hosts, and are not under quarantine restrictions.) Tropical fruits, like guava, mango, and papaya, which are not grown in our region but often sold in open markets, are also favorites of the pest. (See this link for CDFA's abbreviated host list.)
OFF is considered to be one of the most destructive pests in its current range, which includes Southeast Asia, where it appears to have originated, and sub-Saharan Africa, where it has spread rapidly after being introduced only two decades ago. In Hawaii, where it was introduced in the 1940s and subsequently became established, it is a major pest of nearly all commercially grown produce. The combination of a high potential to damage fruit and a very wide host range, as well as its great reproductive capacity, make this pest one of the highest priorities for exclusion from California and other parts of the mainland United States. In addition to costs associated with direct losses of damaged fruit and new management treatments, if this pest were to become established, it would severely impact export markets for nearly all major commodities. Due to its destructive potential, the pest is under aggressive management where it occurs and is subject to exclusion measures in many regions including Europe, Africa and Asia.
Like other fruit fly pests, the damage done to fruit by OFF is caused by the larval stage. Female flies insert eggs into the flesh of ripe or, less preferentially, green fruits using a piercing organ similar to a stinger called an ovipositor (see photo below). The worm-like larvae feed on the fruit pulp under the skin until they are ready to pupate, at which point they eat their way out of the fruit and drop into the soil. In addition to the risk that consumers find maggots (the larval stage) in the fruit, the damage they cause in fruit make it more susceptible to secondary decay by fungi and bacteria. OFF can go from egg to adult in a little over two weeks, and can be ready to reproduce again in about 30 days, and a single female may lay more than 1,000 eggs in its lifetime!
Regulatory efforts to exclude high impact pests
OFF is one of several exotic fruit flies regulated by the federal government and that are monitored by county agricultural departments in coordination with the state, as part of their mission to protect the state's agricultural producers and the environment from new pests and diseases. Other exotic flies actively under exclusion efforts are Mediterranean fruit fly (MedFly) and Mexican fruit fly. A similar quarantine and eradication were implemented in Solano County for MedFly a few years ago. Unlawfully imported fruit are considered the main way that these pests find their way into the country.
OFF is regularly detected in California, but, fortunately, many quarantine and eradication efforts in the past have been implemented successfully. Most quarantines have been in urban areas that did not substantially affect agriculture in surrounding areas. Unfortunately, the finds in Brentwood have affected significant acreage in and around the city. This is perhaps another challenge of the urban-agriculture interface in our region which otherwise offers many benefits, like the thriving U-pick business. A quarantine and eradication effort have also been put in place for Santa Clara County since late August. Eradication treatments entail the attraction of male flies to "bait stations" containing an attractant and a biological insecticide, which is approved for use in organic agriculture. The process is described in some detail in the CDFA's OFF fact sheet.
What this quarantine means for Brentwood area growers
Growers in the quarantined area (see the map linked here for current boundaries) cannot sell or ship produce off of their property without a compliance agreement. The Contra Costa County Department of Agriculture held a joint meeting with the CDFA at the Knightsen Farm Center on September 7 to explain the quarantine and compliance requirements.
Compliance requires growers to make a certain number of treatment applications on a specified schedule under the supervision of state or county agents The Department of Agriculture will provide details on compliance requirements and treatment options. During warm, summer conditions, treatments can be completed in as little as 30 days, but as we go into the cooler, autumn months, the required treatment window expands due to slower development of OFF. Therefore, it is critical to begin the compliance process with the agriculture department as soon as possible. For produce destined for processing, such as processing tomatoes, winegrapes and walnuts, the requirements are somewhat more flexible, but it is still essential to contact the agriculture department to set up a compliance agreement as soon as possible before harvest.
There are treatment options for organic growers. The quarantine is expected to extend at least through the beginning of next year's growing season, so it is essential for growers to plan ahead for next year's crop, as well.
More information is available at the resources listed below.
* Note that though pumpkin and related types of Cucurbita pepo appear on the comprehensive host list, CDFA authorities have stated that this species is no longer regulated. Please check with the Contra Costa County Department of Agriculture.
References and Sources:
- Oriental Fruit Flies Detected in Contra Costa County Quarantine Forthcoming Contra Costa County Department of Agriculture News Release August 30, 2023
- Oriental Fruit Fly Regulation and Quarantine Boundaries, California Department of Food and Agriculture
- Oriental Fruit Fly Fact sheet, California Department of Food and Agriculture
- Oriental Fruit Fly Pest Profile, California Department of Food and Agriculture
- Current Exotic Fruit Fly Quarantines in California, California Department of Food and Agriculture
- Featured Creatures University of Florida IFAS
- State Takes Emergency Action to Eradicate Oriental Fruit Flies Found in City of Santa Clara. County of Santa Clara Office of Communications and Public Affairs
Scientific articles:
- Capinera, John L. “Oriental Fruit Fly, Bactrocera Dorsalis (Hendel) (Diptera: Tephritidae).” In Encyclopedia of Entomology, edited by John L. Capinera, 2690–92. Dordrecht: Springer Netherlands, 2008.https://doi.org/10.1007/978-1-4020-6359-6_1882.
- Mutamiswa, Reyard, Casper Nyamukondiwa, Gerald Chikowore, and Frank Chidawanyika. “Overview of Oriental Fruit Fly, Bactrocera Dorsalis (Hendel) (Diptera: Tephritidae) in Africa: From Invasion, Bio-Ecology to Sustainable Management.” Crop Protection 141 (March 2021): 105492.https://doi.org/10.1016/j.cropro.2020.105492.
- Wei, Dong, Wei Dou, Mingxing Jiang, and Jinjun Wang. “Oriental Fruit Fly Bactrocera Dorsalis (Hendel).” In Biological Invasions and Its Management in China, edited by Fanghao Wan, Mingxing Jiang, and Aibin Zhan, 267–83. Dordrecht: Springer Netherlands, 2017.https://doi.org/10.1007/978-94-024-0948-2_15.
/span>/span>/span>
- Author: Karey Windbiel-Rojas
Subject: End of the Oriental Fruit Fly Quarantine – Sacramento and Yolo Counties
Effective May 28, 2019 the Department is removing the Oriental Fruit Fly quarantine located in Sacramento and Yolo Counties. Maps of any remaining Oriental Fruit Fly quarantine boundaries can be found at: www.cdfa.ca.gov/plant/off/regulation.html#maps
Process to Appeal the Proposed Area Boundary Change
The appeal must be submitted to the Department in writing and supported by clear and convincing evidence. The appeal must be filed no later than ten (10) working days from the date of this notification. During the pending of the appeal, the designated Quarantine Boundary under appeal shall remain in effect.
Mail Appeals to:
CDFA - Pest Exclusion
1220 N Street
Sacramento, CA 95814
Electronic Notification of Boundary Changes
California Code of Regulations allows interested parties to be notified of quarantine area boundary changes, as well as the opportunity to submit quarantine boundary appeals. If interested in receiving notifications, please sign up for regulatory updates through the email notification ListServ at:
www.cdfa.ca.gov/subscriptions/index.html#planthealth
For questions regarding the regulations or map, please email Jennifer VanDyke at jennifer.vandyke@cdfa.ca.gov or KarLee Wyatt at karlee.wyatt@cdfa.ca.gov or call 916.654.0312.
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