Growers need a little relief in the ongoing war against vine mealybug in California vineyards, but finding that relief has not been easy. Vine mealybug was first identified in California in the Coachella Valley in 1994 and has since swept through the state's raisin, table and wine grape vineyards with a vengeance. Controlling it has been a challenge and that challenge could get more critical if currently registered pesticides are pulled from the market.

Of particular concern, the use of organophosphates in the San Joaquin Valley are under intense scrutiny, according to Walt Bentley, University of California IPM specialist, Kearney Agricultural Center, Parlier, Calif. At a recent Bayer CropScience T&V seminar, Bentley warned that some crop protection materials could be in jeopardy due to low levels showing up in monitoring programs.

“Lorsban is going to be one they will try to pull,” he says. “The recommendations PCAs make regarding any pesticide are going to be impacted because they are going to be scrutinized in greater detail. As an industry, we have to be more concerned than ever about the environmental impact of how we manage pests.”

Lorsban has been a standard treatment for vine mealybug as a delayed dormant and/or post harvest application.

The search for increasingly “softer” and less invasive materials is ongoing and will only intensify as the urban landscape continues to encroach upon California's commercial agriculture.

Stopping vine mealybug before it becomes established has never been more critical, according to Bentley. “It's extremely important to recognize early infestations and act immediately,” he says. “Growers need to look at the situation like they are treating one sick calf instead of waiting for it to infect the entire herd. One infested vine is a problem that should be addressed immediately. Vine mealybug is a problem that will definitely cost you more later if you don't do something about it now.”

Control options

Options to battle a pest as potentially devastating as vine mealybug are almost a godsend. One product in the pipeline that looks promising is Movento from Bayer CropScience. Bentley has been evaluating the product in university research trials.

“We would like to go to reduced risk materials to help build predators early,” he says. “Movento has been very effective at controlling vine mealybug. It takes a while to get it in the plant, but it looks good.”

Movento's systemic activity could be a huge plus for vine mealybug control which is often thwarted by the pest's mobility throughout the year. It can move from plant roots to leaves to the underside of the bark, and those movements are not entirely predictable. Infestation and movement also vary among California's different growing regions and climate zones. Contact insecticides can fall short simply due to the pest's ability to protect itself below the soil and under the bark. Vine mealybug is a phloem feeder, however, and that characteristic alone makes systemic control potentially more viable than contact materials.

Movento is still a year or so away from registration — probably in late 2008 if all goes as anticipated. Its potential for targeted control of high priority pests such as vine mealybug with minimal impact on beneficials should work to keep the product on the current regulatory time track, according to Bayer.