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High leafhopper survey counts cause alarm

California agriculture officials caution desert growers over troublesome pest.

Todd Fitchette, Associate Editor

June 17, 2024

2 Min Read
Sugar beets
Sugar beets mature under a warm sun at the Desert Research and Extension Center in Holtville, California. State officials in May recorded high counts of beet leafhoppers in sweep net surveys in the southern California desert from the Salton Sea to El Centro. These leafhoppers can vector a troublesome disease for sugar beet growers in the region.Todd Fitchette

Imperial County farmers from the Salton Sea to El Centro are being warned by California officials of high beet leafhopper counts in survey sweeps.

These leafhoppers can vector a troublesome disease in various crops known as beet curly top virus (BCTV). The disease is particularly troublesome in sugar beets, though it can affect other crops.

Personnel from the state’s beet curly top virus control program, which is part of the California Department of Food and Agriculture, found average sweep net counts at or above 25 adults and nymphs in various surveys of roadside vegetation from east of State Highway 111 to northeast of Brawley, and west of Hwy. 111 to Interstate 8. The surveys were conducted in late May.

Surveys of roadside vegetation included goosefoot, saltbush, and Russian thistle, according to a statement from the CDFA. The statement further cautions that activity in fallow fields or the removal of host vegetation could increase the displacement of leafhoppers into neighboring farm fields.

“I’m not surprised that there are beet leafhoppers this year in Imperial County, considering the amount of winter/spring rainfall they received, which led to more germinating and robust growing of weeds and desert plants than in typical years,” said Michael Rethwisch, a farm adviser with the University of California Cooperative Extension in Riverside County.

Rethwisch further said the one bright spot in the latest insect discoveries is that the desert sugar beet crop is largely done for the year. The greatest damage to sugar beets from these insects tends to be with the younger plants, he said.

Many crops affected

Ana Pastrana, a plant pathology farm advisor with UC Cooperative Extension in Imperial, San Diego, and Riverside counties, wrote in a recent Extension newsletter that BCTV has a wide host range, affecting such crops as beans, tomatoes, peppers, melons, sugar beets, and other crops.

“Yield losses due to curly top can vary significantly from year to year and are often associated with high leafhopper populations,” she writes.

Beet leafhoppers are less than a quarter inch long, and pale green to gray or brown in color, according to the University of California. While they can cause relatively minor damage from feeding, the main concern is their ability to transmit BCTV and other related viruses.

Weed control in areas surrounding farm fields can help reduce BCTV inoculum, according to UC Integrated Pest Management documents. Furthermore, UC IPM experts report that foliar insecticides have not proven to be effective in controlling the insect or reducing the incidence of BCTV when applied to sugar beets.

Rethwisch tells Western Farm Press that insect control is challenging, even with pyrethroid insecticides as coverage in a near-full canopy crop like sugar beets is hard to achieve. As temperatures increase above 100 degrees, the efficacy of pyrethroids is “much reduced,” he added.

Imperial County harvested over 1 million tons of sugar beets in 2022, according to the county’s annual crop report.

About the Author(s)

Todd Fitchette

Associate Editor, Western Farm Press

Todd Fitchette, associate editor with Western Farm Press, spent much of his journalism career covering agriculture in California and the western United States. Aside from reporting about issues related to farm production, environmental regulations and legislative matters, he has extensive experience covering the dairy industry, western water issues and politics. His journalistic experience includes local daily and weekly newspapers, where he was recognized early in his career as an award-winning news photographer.

Fitchette is US Army veteran and a graduate of California State University, Chico. 

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