Fresno County hops into action to eradicate BLH

County grants commercial growers permission to use restricted pesticides on invasive beet leafhopper species to protect tomato crops

The beet leafhopper, otherwise referred to as BLH, is an insect that carries the disease Beet Curly Top Virus, which is deadly to tomato plants. (Courtesy of the University of California Agriculture & Natural Resources.)
The beet leafhopper, otherwise referred to as BLH, is an insect that carries the disease Beet Curly Top Virus, which is deadly to tomato plants. (Courtesy of the University of California Agriculture & Natural Resources.)
Darren Fraser
Published April 23, 2024  • 
12:00 pm

FRESNO COUNTY – Fresno County’s Administrative Officer has made an emergency declaration to combat the invasive post known as the beet leafhopper (BLH), effectively giving local growers the opportunity to use the pesticides that are typically restricted.

County Administrative Officer (CAO) Paul Nerland declared the emergency on April 17. This allows commercial growers in the county to use neonicotinoid pesticides to stop the spread of BLH, an insect that carries the Beet Curly Top Virus (BCTV), which is deadly to tomato crops. 

The Fresno County Board of Supervisors (Board) will vote on the emergency proclamation at its meeting on April 23. As director of emergency services, Nerland does not require the Board’s approval to enact the emergency, but the Board’s vote serves to reaffirm the emergency declaration.

Fresno County Agricultural Commissioner Melissa Cregan said the emergency declaration is the first step in paving the way for the use of neonicotinoids.

“Beet leafhoppers are not a new problem,” said Cregan. She added that the county has been dealing with the pest at least since the 1940s. And while the insects represent an annual concern, the DPR’s new regulations warranted the need for an emergency declaration.

Neonicotinoid pesticides aren’t often used aside from emergency cases because of the threat they pose to pollinators, such as honeybees. However, according to the local emergency proclamation, the financial threat BLH and BCTV poses to commercial tomato crops is significant. 

California is the largest producer of processed tomatoes and the second largest producer of fresh tomatoes in the country. According to the Fresno County Department of Agriculture and Weights and Measures 2022 crop report, tomatoes ranked as the county’s seventh largest crop – up from eighth place in 2021 – with a total value of $429,263,000.

Fresno County’s Agricultural Commissioner estimates that without the use of neonicotinoids, 70% to 90% of tomato crops could be damaged by BCTV. And if growers are restricted to using non-neonicotinoids, treatment costs could increase by as much as 130% or up to $7.8 million. Because the virus is particularly deadly to young plants, at minimum, 50% of the total fresh market and processing tomato acreage is at risk in the Valley.

This year on Jan. 1, the California Department of Pest Regulation (DPR) rolled out new regulations on the use of neonicotinoids. According to a DPR fact sheet, pollinators, such as honeybees, are at risk from neonicotinoids because the pesticides move throughout a plant’s tissue. Honeybees ingest contaminated pollen or nectar.

“There is no ban on neonicotinoids,” said Cregan. “There are restrictions about when they can be used.” She added that restrictions apply to crop groups. Tomatoes are part of the fruit and vegetable crop group. 

According to the DPR fact sheet, over 50 crops are covered by the regulations. The sheet notes there are four exemptions to the regulations, including “an application made to address a local emergency or to control a quarantine pest.”

As of report, Cregan said growers are not yet using the pesticides. The purpose of the emergency declaration is to ensure when the need comes to apply the pesticides, there will be no delays.

“My department will inform the growers when that time comes,” she said. She added that Nerland’s declaration gives her the authority to allow the use of neonicotinoids; however, that authority is specific to BCTV and tomatoes.

During the winter, BLH live in the Coastal Range foothills west of the Central Valley. The insects lay their eggs on various perennial weeds. These weeds become infected with BCTV.

According to the California Department of Food and Agriculture (CDFA), after they exhaust that particular food supply, BLH migrate to the Valley floor in search of more weeds; absent these, the insects gorge on plant crops, spreading BCTV. This annual migration coincides with the start of the growing season when crops are at their most susceptible.

The CDFA warns that while most BCTV infections occur at the start of the growing season, crops are susceptible throughout the entire season because the insects can live on the Valley floor for as long as three generations. Typically, the insects return to the foothills in late fall.

Nerland’s proclamation states the emergency remains in effect for 60 days from the date of the Board’s ratification. If the emergency extends beyond 60 days, Nerland and the Board will make the determination to continue the emergency.

Darren Fraser