IPM alive and well in San Diego

Local growers are using beneficial insects to control pests on important crops like avocados and strawberries. These tools are available for you to use, too.

Information provided courtesy of the San Diego Farm Bureau and County Department of Agriculture, Weights and Measures
ow, more than ever before, farmers are looking for alternative ways to control the pests that threaten our food and fiber. Beneficial insects, such as ladybugs, are one alternative farmers are using more and more frequently.
Several pests have been controlled recently in San Diego County using IPM strategies. These include omnivorous looper on avocados and vegetable crops, citrus thrips and whitefly pests, puncture vine, wilt and seed-borne diseases of vegetable crops.
The Department of Agriculture, Weights and Measures has undertaken a cooperative IPM effort with the University of California, Riverside to control the exotic Formosan Termite. The use of a bait that is toxic only to termites shows great promise as a safe, effective long-term control measure for these tropical pests. The Department is also working with industry and the university to develop an effective IPM strategy for the Persea mite on avocados.
In 1993, the San Diego County Pesticide Task Force completed its final report and devised a pesticide reduction policy for the County. This policy increases the County's use of IPM strategies in County-owned facilities and is intended to decrease dependency on chemical control methods.
The use of insects, though, is more complicated than spraying pesticides. The important information needed to understand how to make the beneficial insects work is discovered through research and testing. These projects can take from one to 15 years to complete as farmers test the insects on their own farms before adopting the new practices. Despite such long timeframes, there have been notable successes in California agriculture. Many research projects are currently underway.

Success stories

Almost all the citrus grown in Southern California relies on a tiny wasp, Aphytis, to control its primary pest. By eliminating the sprays for this pest, nature is able to balance the populations of other insect pests and maintain them below economically damaging levels. Before the introduction of Aphytis, most citrus groves were sprayed 4 to 5 times per year. Now, only small areas - perhaps 10 percent overall - are treated once a year.
In strawberries, a small, predaceous mite was discovered that feeds on spider mites, the primary pest of commercially grown strawberries. Rather than frequent spraying, over half the strawberry growers in the state now use these beneficial mites to control pest mites.
Research projects are also under way in almonds, lettuce, tomatoes, grapes, and many other crops.
A local insectary, American Insect-aries in Escondido, grows predators and parasites to control whiteflies in vegetables and flowers. If you would like to learn more about pests and beneficial insects, look for Good Bugs For Your Garden by Allison Starcher (around $12 in bookstores). If you would like to obtain beneficial insects for your garden, please contact Weidner's Greenhouse in Encinitas, at 436-2194 to buy them over the counter.
The Department of Agriculture, Weights and Measures rears beneficial parasites and other insects in an insectary in Chula Vista. This is the oldest continually operating facility of its kind in California. The Department's overall goal in its biological control program is to create a functional pest management program using classical biological control techniques where feasible to replace pesticides in San Diego County.
Projects to achieve biological control of whiteflies, woolly apple aphid, Nantucket pine tip moth, mites, Italian thistle, puncture vine, Klamath weed, hydrilla and various scale insects are ongoing.

Pest prevention

Pest prevention is the first line of defense against the introduction of new pests that have no natural predators and might thrive in San Diego County's temperate climate, causing harm to humans, the environment and agriculture. The County's Pest Exclusion Division inspects incoming packages at all major terminals in the County, including the airport, post office, United Parcel Service, and truck terminals. In addition, the County has an aggressive nursery inspection program.
San Diego County's heavily used air and maritime ports and the international border with Mexico present a constant possibility of new pests being introduced, not only to California but to the United States. Several significant pests were detected in San Diego County during 1995. These pests include eleven Mexican fruit flies, and 21 Japanese beetles. A quarantine has been established in National City covering a 39 square-mile area, and the release of sterile fruit flies until mid-1996 is expected to eradicate the pest. It's important that the methods used to protect invading pests do not impact the health of the surrounding communities.