A century ago, an unlikely-sounding heroine--a chunky, red-and-black Australian lady beetle, the Vedalia--came to the rescue of Southland orange growers, ending a plague of cottony cushion scale that was threatening the region's groves with ruin.
The 1888-89 campaign marked the start in the United States of biological control, a strategy of importing natural enemies to control exotic pests.
The Vedalia's victory over the cushion scale in Southern California was so complete, and the benefits so long-lasting, that 100 years later, most people have never heard of cottony cushion scale, and pesticides are not needed against it.
To commemorate the success of the Vedalia beetle in its fight against cushion scale, a four-day International Vedalia Symposium will begin Monday at UC Riverside to discuss the past, present and future of biological pest control.
Collected Natural Enemies
The Vedalia project was started on $5,000 in government funds paid to an entomologist who collected the natural enemies of cottony cushion scale in the pest's native homeland of Australia for use in the Southland battle.
A century ago it was hard to get government funds for something as radical as importing beneficial insects to fight pests.
Charles Riley, the U.S. Department of Agriculture entomologist who masterminded the effort to bring the Vedalia beetle to California, used subterfuge to get an entomologist to Australia over the objections of Congress.
The lawmakers had barred foreign travel by the Agriculture Department to stop Riley's frequent European junkets. But Riley knew his way around the political scene, and hid an entomologist on a State Department trip to an international exposition in Melbourne.
Rare on Australia
Although a major problem in California at the time, cottony cushion scale was rare in Australia because of natural enemies like the Vedalia.
Entomologist Alfred Koebele relied on Australian experts to guide him to rare pockets of the pest and its natural enemies, a parasitic fly and about 500 Vedalias.
To raise the Vedalia beetles in this country, scientists placed a tent over an orange tree at the J. W. Wolfskill ranch near what is now Union Station in downtown Los Angeles. Some Vedalias were also shipped to the J. R. Dobbins and A. Scott Chapman ranches in San Gabriel.
The original 500 beetles produced millions of progeny, and people came from throughout Southern California to collect lady beetles from the ranches to save their own groves.
'Like a Miracle'
"The deliverance was more like a miracle than anything I have ever seen," said William F. Channing of Pasadena.
A Smithsonian Institution report said "the state went wild on the subject of bringing over beneficial insets from Australia."
In 1929, Los Angeles County's annual horticultural report noted that there were 103 workers on the payroll raising beneficial insects, including 6 million lady beetles that were distributed over 11,000 acres.
Besides a beneficial insect lab in Downey, a house was remodeled to become the Melrose-Highlands laboratory-insectary to raise beneficial insects.
In Fillmore, growers formed their own cooperative district, which is still raising beneficial insects for citrus orchards that have rarely been sprayed with pesticides in the last half-century.
The California Department of Food and Agriculture has compiled a list of about 60 companies selling beneficial insects, such as lady beetles, praying mantises, green lacewings, Encarsia (indoor whitefly parasite), Cryptolaemus (mealybug destroyer), Trichogramma wasps (moth egg parasites) and predatory mites.
The first commercial firm was Rincon-Vitova Insectaries (P.O. Box 95, Oak View, Calif., 93022), which sells to large commercial farms. Beneficial Insectary (14751 Oak Run Road, Oak Run, Calif. 96069) caters to gardeners with garden variety packs of ladybugs, green lacewings, Trichogramma, fly parasites, praying mantises and red worms for $25.
Plants That Attract
Even without making special releases, many beneficial insects are naturally attracted to gardens to perform pest control chores.
Flowering plants, particularly members of the Umbelliferae, like Queen Anne's lace, angelica, sweet cicely, coriander, parsley, dill, carrot, celery, caraway and fennel attract beneficials. Amaranth is excellent because it flowers provide beneficial insects with nectar and pollen.
Early-season pollen and nectar sources give beneficials alternate food sources while waiting for pests to appear, while mid- and late-season flowering food sources provide sustenance to keep the good guys in the garden between pest infestations.
Corn and sunflowers make good roosting places for green lacewings--shaking the plants spreads the natural enemies out around the garden.
Potential Not Realized
The potential use of biological control for the urban environment has barely been tapped, scientists believe.
The UC Cooperative Extension agent for Los Angeles County, Donald Hodel, worked with a team headed by former UC Riverside Extension entomology specialist A. D. Ali in releasing predatory mites to control pest spider mites plaguing plants in banks, hotels and other interior areas.
"We were successful in controlling mites on palms in the interior landscape by introducing predatory mites on the plants," said Hodel, who released the beneficials in a Los Angeles hotel.
Hodel does not know if these applications are being commercialized, although the advantages for those wanting to control pests in public areas without risking pesticide liability are great.
The morning sessions of the Riverside symposium will feature talks for the general public, while afternoons are technical sessions for international researchers to exchange information.