Pesticide program aims to stop sharpshooter spread
Ag Commissioner’s Office says there have been no reports of human illness in program’s 21-year history
By Kaitlin Washburn @kwashy12
VISALIA – Pests and the diseases they carry are a constant threat to the livelihoods of agricultural communities.
For grape growers, glassy-winged sharpshooters can devastate entire vineyards thanks to the bacteria the pest carries, Pierce’s Disease.
The Tulare County Agricultural Commissioner’s Office conducts pesticide programs in residential and urban parts of Visalia and Lindsay to stop the spread of the sharpshooter to neighboring vineyards. Some residents within those areas are supportive of the programs, while others are wary of pesticides in their neighborhoods.
“We always weigh the importance of agriculture as an economy and an industry,” said Jonathan Bixler, a Tulare County deputy agriculture commissioner. “Agriculture is vital to this area, and we must do what we can to protect it.”
Glassy-winged sharpshooters, dark brown, winged insects with black and yellow underbellies, have been an issue in California since the 1990s, and were first detected in Northern California, Bixler said.
While the sharpshooter enjoys produce like grapes, oranges and avocados, the pests are found in residential areas and lay most of their eggs in landscaping plants.
In the past, Tulare County attempted an eradication program to address the sharpshooter, Bixler said. But now, the commission is only working on containing the pest.
Five to six months of planning happens before the pesticides are sprayed, Bixler said. The commission first draws up a map of the affected areas, which is then sent to the California Department of Food and Agriculture (CDFA). The state does an environmental impact report of the area to make sure no serious harm would be done to the environment.
Before applying pesticides, biologists conduct visual surveys to find where the sharpshooters are. Until they enter adulthood, sharpshooters generally stay on the plant where they hatched.
If sharpshooters are identified on a property, the resident receives a 48-hour notification from the county before the landscape is sprayed. The notice, a bright pink paper posted to the resident’s door, explains the program, the treatment process and the pesticides used.
Over 99 percent of residents have accepted the treatment, Bixler said. To opt out of the spray, residents need to contact the commissioner’s office.
The commission contracts Res-Com Pest Control to do the pesticide treatments. Most of the time, a systemic drench method is used to apply the pesticide. The county uses Merit, a CDFA-recommended pesticide for glassy-winged sharpshooters.
The insecticide’s active ingredient is imidacloprid, which is also found in home gardening products and flea treatments. The chemical binds to the pest’s nerve cells, shutting down its nervous system, according to the California Office of Environmental Health Hazard Assessment (OEHHA).
The chemical can harm the nervous system, liver, thyroid and body weight of humans and animals. However, when Merit is used correctly, the low levels of imidacloprid shouldn’t cause such health effects, according to OEHHA.
Imidacloprid also demonstrates the properties and characteristics of chemicals found in groundwater, according to the Merit safety label. If the chemical is used where soils are permeable, it could lead to groundwater contamination.
This program has been administered for 21 years, and Bixler said there have been zero reports of human illness, domestic animal illness or bee deaths from the pesticides.
To use the drench method, the pesticide is mixed with water and sprayed at the base of the plant. The treatment is usually done in the morning since the sharpshooters are more active later in the day when it’s warmer. The method is used to protect bees, especially during the spring, Bixler said.
The foliar method, which is when the pesticide is sprayed directly on the plant, is avoided unless there’s a major sharpshooter infestation, Bixler said.
“It’s a very targeted method,” Bixler said. “These pesticides can be very safe when applied in a conscious and controlled manner.”
Bixler said the biggest misnomer he has heard from residents is that every property is sprayed. The county is only spraying where there has been a known sighting of sharpshooters. The map’s boundaries are updated whenever new sharpshooters are found, Bixler said.
The treatment area in Visalia roughly resembles a donut, with a spray-free zone in the middle that includes Highway 198 and parts of downtown Visalia.
The border of the treatment area is jagged. To the west, the boundary starts at South Demaree Road and the far eastern edge is South McAuliff Street. The northern boundary of the donut is West Riggin Avenue, West Prospect Avenue and West Houston Avenue. East Caldwell Avenue is the southern border.
Oleanders are a major host for the glassy-winged sharpshooters, and they are grown along Highway 198. Since that is California Department of Transportation territory, the commission doesn’t apply pesticides there, Bixler said.
CDFA is releasing small, parasitic wasps along the highway to combat the sharpshooters in that area. The wasps lay their eggs in sharpshooter eggs, which kills the pest. The commission doesn’t spray parts of downtown to avoid interfering with the wasps, Bixler said.
In Lindsay, the treatment area is a simple rectangle within the boundaries of Fir Street, Lindmore Street, North Westwood Avenue and Foothill Avenue.
CDFA sent about 30,000 letters to residents within the identified area explaining the program and inviting them to a town hall meeting held by the commission on May 21. About 100 people showed up to the meeting, Bixler said.
There was a mix of attendees for and against the pesticide application. Bixler said the people against the program were either misinformed or just anti-pesticide.
Residents also spoke out about the pesticide program at a recent Visalia City Council meeting.
Daniel Garcia and Paula Bayard, both Visalia residents, were upset about how the county informed residents about the spray. Garcia said a letter isn’t enough to properly inform residents, and Bayard said the literature about the pesticide wasn’t balanced.
Bixler said it’s difficult to reach everyone in a community, but he has considered other ways of notifying people, such as a Facebook post.