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.