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Riverside man raises beneficial insects Alternative to massive pesticide use

By TOM PATTERSON

The Press, Riverside, CA, 7-31-1973

Producing beneficial insects to fight insect pests is a rapidly growing business for Everett Dietrick, former biological control scientist at the University of California, Riverside.

His firm is expanding; an indication that total reliance on the massive use of insecticides is waning. Dietrick's company, Rincon-Vitova Insectaries Inc., with 21 employees, operates on El Rivino Drive in the Rubidoux area and at Oak View in Ventura County. It is starting a new and potentially larger operation in a former defense laboratory near Milpitas, to serve central California agriculture.

This, he explained, "is a very small drop in the bucket compared to the multi-million-dollar pesticide business." He is competing with that business, not with the idea that no one should ever spray insecticides on bugs. He does believe that the all-out spray chemical programs are falling as long-term solutions and that there will be more emphasis on his approach.

He identifies himself with integrated control - using sprays only when only where a clear and present danger exists.

Dietrick sells two products -insects and advice. He and his associates contract to provide pest management by the acre to farmers. Some independent entomologists are also selling integrated control advice, he said, most of them use Rincon-Vitova as a source of beneficial insects.

He modestly increasing success, Dietrick said, "is due to economics, not to moral preachments about ecology. The all-out use of insecticides reaches a point where the cost keeps rising and production goes down. ...But it's awfully hard to get away from a program that has been successful. Even though the new insecticides cost a lot of money, they worked; or, if one didn't work, another was found that would."

Dietrick's company improvises. He utilizes outmoded refrigerator freight cars to insulate his insect rearing, to hold down air-conditioning costs.

On rows of banana squash on shelves, scale pest insects are growing in heavy incrustations, and this presence of pest insects says something about biological control.

"IN ORDER TO produce good insects, you must have bad ones," he explained.

The good ones feed on the bad ones, often on a specific bad one, leaving other insects alone.

In the railroad car where housefly enemies are produced there's a noxious odor of rotting stuff - for the flies to eat

The Rincon-Vitova inventory includes the pale green lacewing for use against aphids, mites, moths and caterpillars.

Ladybugs are collected in the field. In the insectary, they are preconditioned so they're ready to feed and lay eggs when they encounter aphids.

Trichogramma wasps, tiny and harmless to people, are parasites on moth and butterfly eggs. They are used to combat the worm pests of cotton and numerous other economic and ornamental plants.

Deke tends banana squash
Everett Dietrick tends his banana squash, hosts to scale insects, which in turn are used as hosts for eggs of the parasitic golden chalcid, a beneficial that attacks red scale in citrus orchards.

SOME BENEFICIAL insects, like lacewings, are sold in larval form. Trichogramma, golden chalcids and some others are sold as adults, ready for release. Fly parasites are delivered while they're maturing in fly pupae, to be placed where they'll emerge to protect poultry or cattle.

The latest Rincon-Vitova product list has 35 different Insect species. The last work Dietrick did as a UCR technician was in connection with the outbreak of the spotted alfalfa aphid in the 1950s. Typically, it had arrived from the Middle East where it is scarce and evidently held under some type of natural biological control. In Riverside County, it multiplied as an insect can under the right circumstances - with a plentiful food supply (alfalfa) and without natural enemies. Several parasite wasps were found In the Middle East to combat the aphid.

"In that work," Dietrick said, "we field-harvested the parasites and moved them to other fields. It took two years to reach a natural balance that might have taken 10 years to accomplish by leaving the parasites to spread natural," DIETRICK SAID many factors contribute to the growers' dilemma with insecticides. Initially, he said, the new insecticides clean fields and groves of harmful insects. The early result is usually big crops with few rejects.

Sometimes, as in Imperial and Palo Verde Valley cotton, the spray program is area-wide - most growers under a uniform contract to spray at regular intervals, whether they need it or not.

Such a program, Dietrick said, eliminates beneficial insects. Eventually, the damaging pests become resistant through the survival and reproduction of the few that are naturally resistant.

By contrast, the integrated control program calls for releasing beneficial insects only after the first damaging ones appear so beneficial ones will have food to encourage them to stay.

ANOTHER PRACTICE goes hand-in-glove with the goal of completely eradicating insects, Dietrick Said - the practice of keeping fields and orchards clean of weeds.

"It saves water," Dietrick explained, "but it also destroys a refuge for beneficial insects. You don't have to leave all the weeds; a row or two in an orchard may suffice."

Or, If cotton mass production is involved, a strip of alfalfa here and there permits beneficial insects to winter.

The pink bollworm pest of cotton, however, poses a problem for biological and integrated control, even as it does for the cotton grower.

It's a godsend, at least temporarily, for the chemical spray industry. No really effective biological control agent is known.

Because he can't control the bollworm but only hold it back a little, Dietrick advises his Coachella Valley clients to spray but not as much as do most cotton growers in the Imperial and Palo Verde valleys.

There, under valley-wide group contracts, growers have had as many as 15 sprays in one season. Most Dietrick clients sprayed only four times, tolerating a higher incidence of bollworm and saving control costs.

But conditions differ. Coachella Valley produces comparatively little cotton, scattered among other crops. Imperial and Coachella Valley cotton grows on larger areas, removed from other crops. This year, foreign purchases have raised the cotton price. Growers are seeking maximum production, leaving biological control for the future.

Dietrick, as well as growers who pay spray bills are hoping that another line of attack on the bollworm may succeed. UCR experimenters have been using a chemical called hexalure, which approximates the chemical used by the female of the pink bollworm to attract a mate.

This opens the way to confusing and misleading the male. It may result in control by natural chemicals, rather than by all-purpose pesticides.

Such control would be compatible with Dietrick's approach to other insect pests, without the harmful side effects of all-purpose sprays.

Although he's primarily in the business of raising insects in insectaries, Dietrick says the integrated control outlook contemplates that most beneficial insects of the future will be raised in the fields.

"That's what we did to control the spotted alfalfa aphid," he explained. "I look forward to a time when I can get most of the insects I need from one field and release them in another nearby. They have a better chance of doing the job when they're raised in the field and they cost less."

 

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