SAREP receives US-EPA grant for biological control of lettuce pests
Adult Hoverfly
Darting between fields of organic romaine lettuce and rows of flowering sweet alyssum, yellow-and-black-striped hoverflies (syrphids) attack lettuce aphid, one of the crop’s most important pests. Aphids and other lettuce pests in California’s Salinas Valley should not look for their situation to improve. In late May 2004, the U.S. Environmental Protection Agency Region 9 approved a UC SAREP proposal entitled “Enhancing Biologically Integrated Farming Systems (BIFS) for Lettuce on the Central Coast Of California.” The grant will provide $196,000 for two years with an option for renewal, potentially totaling nearly $400,000 for a four-year BIFS project.
This project will focus on research and outreach to enhance biological control and other least-toxic tactics for lettuce pest management in the Salinas Valley. The work will be carried out by a team that includes Bill Chaney, UC Cooperative Extension Monterey County farm advisor and colleagues from the private sector, as well as UC SAREP staff (Robert L. Bugg, Janet C. “Jenny” Broome, Bev Ransom). A main goal of the work is to enable lettuce growers to reduce reliance on organophosphate and carbamate insecticides.
“I have been conducting work in this arena for over a decade, including studies on the use of nectar-bearing plants like sweet alyssum to promote hoverflies that attack aphids,” said Chaney. “It is exciting to be able to work with a mix of organic and conventional lettuce growers to take the research and outreach to another level.”
Chaney noted that the organic growers routinely use insectary plants to combat aphids and other pests, a method that can be adapted to conventional production systems.
“We already have a pretty good handle on the problem by just using annual insectary plantings like sweet alyssum. Our planned studies should show us whether we can gain anything by using insectary hedgerows of perennial woody plants,” he said.
Conditions on California’s Central Coast are especially promising because organic growers, including Natural Selection Foods, have extensive experience using sweet alyssum to attract hoverflies and suppress aphids in romaine and broccoli.
Ramey Colfer, an entomologist with Natural Selection Foods, said his data show that hoverflies are the dominant lettuce aphid predators near the coast, but that further inland, lady beetles and bigeyed bugs may become increasingly important.
“We organic romaine growers meet the same cosmetic standards as conventional growers,” he said. “In most cases, the natural enemies, especially the hoverfly larvae, clean up the aphid infestations for us, but sometimes we have to resort to organically approved insecticides. This project should help us better understand how to manage the beneficial insects, so that even organic growers can reduce insecticide use.”
The project will involve Colfer and other cooperators, including Phil Foster and Patrick Troy, as mentor farmers who will assist enrolled growers in understanding, adapting, and implementing the techniques. Another cooperator is Sam Earnshaw of the Community Alliance with Family Farmers (CAFF), who has established many insectary hedgerows on Central Coast farms. Earnshaw, whose background includes organic vegetable production and forestry, will plan and establish a state-of-the-art demonstration hedgerow on an organic farm near Salinas that will serve as a model system for other farmers in the area.
The project will get underway in October 2004, when a postdoctoral researcher will be hired to coordinate the research and outreach. In November, interested growers will be enrolled as participants, and the research, monitoring, and mentoring will begin. For further information, please contact Robert L. Bugg, UC SAREP, at (530) 754-8549, rlbugg@ucdavis.edu.
