2005 Annual Report

UC Statewide IPM Program
HIGHLIGHTS

UC IPM Makes It Happen

Photo by David Haviland

IPM Advisor coordinates worker protection safety training in Kern County

High levels of pesticide exposure incidents in Kern and other southern San Joaquin Valley counties prompted the U.S. Environmental Protection Agency (EPA) to award a $50,000, two-year grant to UC IPM Advisor David Haviland to provide worker protection training to farmers and farm workers in Kern County.

Primarily, these incidents have been the result of drift from ground and aerial applications of insecticides or the off-site movement of fumigants.The project is a collaborative effort of the Kern County UCCE, Kern County Agricultural Commissioner's office, and the UC Statewide IPM Program.

Continued >> The U.S. EPA grant provides funding toward two major education programs. The first program is co-funded through the Kern County Agricultural Commissioner's office and offers a series of 20 meetings for private applicators in Kern County. Training sessions are held at several locations twice annually and focus on the responsibilities of private applicators for the safety of field workers on their properties.

The second objective of the project is to provide a train-the-trainer program for farm labor contractors in the southern San Joaquin Valley. This program will follow the training model developed by the UC IPM Pesticide Safety and Education Program, an innovative outreach program from 1987 through 2004.

This coordinated effort among federal, state, and county agencies and the university promises to help reduce the number of pesticide exposure incidents in the southern San Joaquin Valley, as well as increase farm worker safety throughout the region.

Herbicide-resistant horseweed found in the south Central Valley

Anil Shrestha, UC IPM weed ecologist, and Kurt Hembree, UCCE weed management farm advisor, both based in Fresno County, have confirmed the existence of a glyphosate-resistant horseweed biotype in the south Central Valley. This is the first confirmation of glyphosate-resistant horseweed in California.

Photo by Anil Shrestha

Glyphosate is the active ingredient in several herbicides registered for use in California. The most common brand is Roundup. According to the California Department of Pesticide Regulation, 5.7 million pounds of glyphosate were used by the agricultural industry in 2003.

Continued >> Researchers collected horseweed seeds from the canal banks of an irrigation district in Dinuba and from western Fresno. They grew seedlings from these two sites and tested for glyphosate-resistance at the UC Kearney Research and Extension Center greenhouse. The weed seeds were planted in pots and treated with three rates (1, 2, and 4 lb a.i./acre) of glyphosate at five different growth stages. Generally, the weeds from west Fresno died when exposed to the 1 lb a.i./acre rate, whereas the seedlings and plants from the Dinuba area survived a glyphosate application rate of up to 4 lb a.i./acre.

"The irrigation district had been continuously using glyphosate alone for weed control on the canal banks for about 15 years," says Anil. "This continuous use of the same herbicide group may have caused the resistant biotype of horseweed to evolve over the years."

To help growers combat this weed, which has become more widespread, Anil and Kurt have now teamed up with UCCE farm advisors Ron Vargas and Steve Wright and are working closely with industry personnel, PCAs, and the irrigation district manager to help manage this problem.

Researcher grows sunflowers to protect peaches from pest

If IPM Advisor Walt Bentley has his way, sunflowers will offer a ray of hope in the battle against the oriental fruit moth.

The oriental fruit moth is one of the most important pests of peaches and nectarines in the world. The female moth lays eggs on the fruit, and the eggs hatch into larvae which immediately attack the center of the fruit and feed around the pit, making the fruit unfit to eat.

Photo by Walt Bentley Lee Martin, retired staff research associate UC Davis, and Matthew Takeda, a student assistant, are part of a team of researchers using sunflowers to fight oriental fruit moth.

Continued >> The oriental fruit moth entered the United States on flowering cherries imported from Japan in 1916. The pest quickly spread throughout the United States but did not reach California until 1942, prior to the development and use of synthetic contact poisons such as DDT.

Because available insecticides used prior to WWII were ineffective against this pest, the USDA developed a program of mass production of a parasitic wasp that effectively manages the oriental fruit moth in those states East of the Rocky Mountains. The wasp lays its eggs inside the pest's larval stage, and then the wasp larva develops within, killing the pest. Once DDT became available, the parasite release program was stopped in most states.

The parasitic wasp does not survive without a host through the winter on oriental fruit moth, and it had to be reared and provided to farmers annually for release in orchards. The decline of this biological control program over the years was due to the easy use and effectiveness of new insecticides, which also killed the wasp.

But, if Walt's research bears fruit, the parasite will be able to live inside the sunflower moth caterpillars through the winter; reducing or eliminating the need to use insecticides on late- harvested fruit. "We've always had good management of the oriental fruit moth when fruit is harvested before August when we're using mating disruption," says Walt. "Our problems occur with fruit harvested after July. There we often have used supplemental sprays. Macrocentrus may be able to eliminate the need for these sprays that occur late in the season."

Control of the oriental fruit moth has contributed to the continued use of broad- spectrum pesticides in stone fruit in the San Joaquin Valley. Currently, pesticides are used along with mating disruption to manage this pest. But infestation has continued to occur in varieties harvested after August, necessitating the use of late-season insecticides. Since regulatory agencies have targeted these insecticides to be phased out because of surface-water contamination, an IPM approach is needed.

With support from the UC Specialty Crops Grant Program, Walt has planted sunflowers on a 1/3-acre patch at the Kearney Research and Extension Center in Parlier, California, next to a peach orchard infested with oriental fruit moth. To date, his sunflower harvests have showed no damage from the pest.

Walt's research shows sunflower moths can help provide a higher population of the beneficial parasite earlier in the season while maintaining the oriental fruit moth at lower levels. Used in conjunction with mating disruption, parasites living in sunflowers planted near a peach orchard could control late-season infestations, eliminating the need for supplemental sprays.

Mating disruption makes use of the insect's own sexual scents, or pheromones. Researchers tie little chips with the female pheromone onto branches; the pheromone confuses the males and disrupts the mating process. The dispensers, which are acceptable for produce certified as organically grown, are placed in trees at the first sight of an oriental fruit moth in late February to early March. Current products will last into August, but fruit harvested later needs the additional help of parasites.

"Our experiments indicate that parasitism is greatest in late-harvested orchards from late July on," says Walt. "We believe this high level of parasitism will result in low survival for the oriental fruit moth in subsequent years, making mating disruption even more effective. We now plan to expand this biocontrol effort to late-harvested peaches and nectarines, combined with mating disruption, to reduce late-season insecticide sprays."