Lygus Bug Control in Strawberries Can Prevent Significant Damage

By Patrick Cavanaugh, Deputy Editor

Adult Lygus Bug, Jack Kelly Clark, UC IPM

Adult lygus bug, Lygus hesperus.
(Photo by Jack Kelly Clark, UC IPM)

In the coastal areas of California where the majority of strawberries are grown, the top pest pressure comes from the lygus bug. Hillary Thomas, senior production research manager with Watsonville-based California Strawberry Commission, works on lygus bug control in strawberries, as it causes significant damage to the crop each season.

“We conservatively attribute between $150 and $250 million in damage each year to the lygus bug alone,” Thomas said. “We have only a few tools to handle this pest, including insecticide and vacuums, that can be used for the strawberry industry.”

Thomas explained vacuum use is widespread by both conventional and organic growers despite its drawbacks, beginning with the huge investment required by the grower. The vacuum is generally tractor-mounted with three or four vacuum fume hoods to one hydraulic system, and the entire vacuum system runs off the tractor’s PTO (power takeoff). The vacuum is so difficult to remove, it is typically installed on the tractor for the entire season.

Therefore, current research aims to make the vaccuum more useful, according to Thomas, by focusing on technological innovations to improve vacuum efficiency. She explained, “We are literally trying to suck up as many bugs as possible by moving the largest cubic volume of air and killing all the insects that move through the vacuum. We have created some standard operating procedures for vacuums as well as recommended short-term modifications to improve their efficiency by 25 percent. The Commission has also developed a series of trainings to disseminate information on the best management practices vacuums for growers.

Strawberry Meeting Focused on Fumigants, Pest Control

Fumigation Was Big Topic at Santa Maria Strawberry Meeting

New laws and regulations on fumigation for Santa Barbara and San Luis Obispo County strawberry growers were in place for the first time this season, and growers did a good job for the most part. This and other topics were discussed at the Wednesday’s annual Strawberry Production and Pest Management Meeting in Santa Maria.

According to Lottie Martin, Ag Biologist, Santa Barbara County Ag Commissioners office, for the most part, grower chose the right tarps for the right situation. “Growers must be careful to use a 60 percent tarp when capping a fumigation with the

Surendra Dara, crop advisor, UC Cooperative Extension, San Luis Obispo

1,3 D,” said Martin. “Growers should plan well in advance to make sure the tarp that is needed, is available.”

Martin said mandated buffer zones were noted and documented, however operators need to do a better job with required signage.

Surendra Dara, a Strawberry and Vegetable Crops Advisor, UC Cooperative Extension, San Luis Obispo, spoke about re-evaluating lygus bug IPM tools in strawberries with a focus on field vacs, monitory and economic thresholds. He spoke of an experiment with softer chemistry such as well as using B. bassiana, a soil fungus that acts as a parasite to lygus. “A combination of B. bassiana and azadirachtin.

Hillary Thomas, research manager, California Strawberry Commission

Hillary Thomas, Research Manager with California Strawberry Commission in Watsonville also spoke about lygus. Her focus was third year bug vac research for lygus control.

Kirk Larson, pomologist and strawberry production specialist with the UC South Coast Research and Education Center, Irvine

Kirk Larson, Pomologist and Strawberry Production Specialist with the UC South coast Research and Education Center, Irvine spoke about advanced selections and non-chilling plug plants.

Mark Bolda, Strawberry and Caneberry Farm Advisor and County Director with UC Cooperative Extension, Santa Cruz County spoke about strawberry transplanting and the critical importance of chilling hours necessary for strawberry production.

Steve Fennimore, Cooperative Extension Specialist, UC Davis updated attendees on the use of steam to kill soil pathogens, in place of fumigants. He said work is focused on reducing the cost and outlined possible use of a prototype machine around certain higher risk areas near buffer zones on production fields.

Karen Klonsky UC Cooperative Extension specialist

Karen Klonsky, Cooperative Extension Specialist, UC Davis spokes about the economic considerations of alternatives to fumigation and producing a second year crop.

Also speaking was Thomas Flewell, Flewell Consulting, Watsonville-Salinas. His topic focused on evaluating pest management strategies with numbers. What do the numbers mean and how do we really know what we’re doing.

A more detailed report can be found in future issue of Vegetables West Magazine. Free subscription at VegetablesWest.com.