Tomatoes Raised to Turn Against a Great Admirer--the Caterpillar

Tomatoes may soon become deadly enemies of the caterpillars that love to gnaw on them.

A gene from bacteria that researchers say cannot hurt other living things will be inserted in tomato seeds, letting plants and fruit that germinate from those seeds ward off caterpillar-type insects without use of artificial pesticides.

Dine and Die

“When the insect eats the plant, it ingests that bacterium and dies,” said David C. Hulst, director of Hulst Research Farm Services, where a field trial on caterpillar-resistant tomatoes is being conducted this summer.

The bacterium, Bacillus thuringiensis, is fatal only to organisms with a specific alkaline level in their systems, making it dangerous only to the caterpillar family.

Hulst said the bacterium is nature’s way of controlling the number of caterpillar-type insects.

“It’s one of those antagonisms put in nature to reduce populations of certain insects,” Hulst said during a tour of the test field. “It is possible that without (this bacteria) in the environment, the insects might eat everything around.”

The U.S. Department of Agriculture agreed to the field test at Monsanto Co. last month, but approval for general use is several years away, said Roy Fuchs, a Monsanto researcher who directed the laboratory work that prepared the way for field tests.

Researchers predict widespread use of this biological control because of growing concern about environmental effects of pesticides that do not always keep insects at acceptable levels, Fuchs said in a telephone interview from his office in St. Louis. He cited Department of Agriculture statistics that farmers spend $150 million annually on chemical insecticides, but caterpillar-type insects alone cause $450 million damage a year.

“There’s a real need for alternatives,” Fuchs added. “That’s what will make or break the technology for farmers--to see a real benefit. And we’re confident they will when they have a chance to look at . . . insect-tolerant plants.”

History of Use Cited

A big advantage of the bacteria approach is “that it has a very long history of safe and effective use in agriculture,” said Trevor Suslow, spokesman for DNA Plant Technologies, a pesticide laboratory that is not directly involved in the tomato research.

However, he said one major concern is that widespread use of bacterial pesticides will cause insects to develop resistance more quickly.

Field tests are being conducted at four locations by independent contractors to give Monsanto and Environmental Protection Agency researchers a broad geographic spectrum of the types of caterpillars the new tomatoes will kill.

Tests began in Illinois two years ago and have spread to Florida and Mexico to see if they will halt tomato pinworms and to Hughson 100 miles southeast of San Francisco to determine the effect on tomato fruit worms and beet army worms. The protein has also been tested on tobacco plants.

Fuchs said taste tests will be conducted later, but he does not think the protein will alter the flavor of the tomato.

Monsanto, which hopes to begin licensing the results of its gene research to seed companies by the mid-1990s, is also studying its use to control cotton bollworms and is looking into its possibilities with other vegetables.

“Any vegetables that have caterpillar insect problems could benefit from this technology,” Fuchs said.