Working Out the Bugs

Every seven years in the woodsy pocket of Connecticut where she grew up, Pamela Marrone would feel the droppings of gypsy moth caterpillars raining down on her head as the cyclical pests gorged on maples and oaks.

Desperate to save a heavily infested dogwood, her father once ignored his own organic gardening tenets and blasted the tree with a chemical called a carbamate.

By the next morning, every bee, every ladybird beetle, every lacewing--all the “good” bugs that fed on plant pests--lay dead on the ground.

Today, Pam Marrone is an entomologist, devoting 60-plus hours a week to hunting for natural products that can defeat plant scourges without wreaking havoc on human beings, animals, helpful insects or soil.

AgraQuest Inc., the start-up she co-founded here in Davis, is one of a handful of laboratories on the leading edge of developing so-called biological controls to protect crops--an old idea that environmental concerns are making fresh again. Driving the quest is pressure from government and consumer activists to reduce the use of synthetic chemicals on the nation’s farms and ranches.

Hoping to make agriculture more environmentally correct, scientists are experimenting with a host of strategies--from using scents to disrupt the sex habits of moths to luring helpful ladybugs into fields with nutritious “power bars” to prospecting for natural disease fighters in unusual places.

Consider Success, a newly approved natural insecticide from Dow AgroSciences, which was developed from a pest-fighting bacterium in soil samples from the Caribbean. A Dow scientist vacationing in the early 1980s had gathered them from under an abandoned rum still.

“The era of chemical-based pest management is coming to an end,” said Charles M. Benbrook, a longtime consultant on pest management based in Sandpoint, Idaho. “The era of biologically based pest management is quickly coming on.”

Biological controls are indeed making great strides, but Benbrook might be overstating the case.

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Despite a fair amount of hype in the past, biological control has never achieved anything close to its potential. A decade ago, proponents forecast that natural products would capture half of all pesticide sales. Yet companies found it expensive and time-consuming to develop biopesticides that worked as fast and as cost-effectively as synthetics.

Today, sales of natural controls remain a minuscule $250 million or so, contrasted with the $10.4 billion spent in the United States for pest-killing synthetic chemicals in 1995.

Indeed, weaning growers off synthetics could prove a tough sell.

Until the advent of synthetic chemicals after World War II, farmers used nothing but natural methods to protect crops. Once chemicals hit the scene, Americans embraced them as a pest-killing panacea in fields, gardens and homes.

Sales of weed and insect killers have marched steadily upward. Meanwhile, hundreds of pests have developed resistance to popular chemicals, making them harder to control and putting farmers on a pesticide treadmill. Pesticides now must be applied two to five times to accomplish what a single application did in the 1970s.

Intensive chemical use also carries a toll in contaminated drinking water and depleted soil, not to mention possibly toxic effects for humans, a subject of tremendous debate.

But advocates of biological control see hopeful signs:

* The boom in the $4-billion organic food industry is showing that there is a market for foods grown mostly without the use of synthetic pesticides.

* The federal Environmental Protection Agency in recent years has eliminated many safety-testing requirements for products deemed to be “reduced-risk,” streamlining the registration process. Since late 1994, about 60 such products have been registered, many by small companies.

* Under the Food Quality Protection Act of 1996, the EPA could soon curtail the use of many prominent synthetic pesticides, leaving growers to scramble for alternatives.

The effect could be felt particularly in California, which primarily grows “minor” crops such as lettuce, broccoli, cabbage, cauliflower and pears. Companies developing crop-protection treatments tend to funnel research dollars into commodity crops such as wheat, corn and soybeans.

* The EPA and the U.S. Department of Agriculture have jointly dictated that by 2000, 75% of all crop acreage must be operating under “integrated pest management” strategies, including tactics that prevent infestations and biological controls to hold pest populations to acceptable levels.

This has spurred industry and university researchers to tap the rich stores of nontoxic treatments that nature provides. Some companies are finding it can be easier to literally look under a rock for safe new pesticides than to synthesize chemicals that might have their roots in nerve gas or other highly toxic products.

Using simple technology borrowed from restroom deodorant dispensers, Harry Shorey, a UC Riverside entomology professor, is pumping new life into a 30-year-old concept: mating disruption.

Male and female moths do not congregate together. When a female is ready to mate, she emits a scent. A male catches the scent and follows the trail upwind.

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Shorey’s experiment aims to confuse that natural pattern. He and his crews are installing aerosol cans in cabinets at 10,000 sites in orchards and fields in the west Central Valley and near Oxnard. Much like a deodorant dispenser, the cans puff a scent into the air that is designed to overwhelm male moths and make them unable to track the females.

Scientists have identified hundreds of these sexual scents, or pheromones. Because they are expensive to mimic, companies have synthesized only half a dozen.

Shorey plans to get the most bang for the puff by placing specially designed puffer cabinets at the perimeters of 40-acre blocks in neighboring fields. The idea is to put large amounts of pheromones into the air--with the amount of scent in each puff equaling that of as many as 10 million moths.

In test runs, Shorey said, he was able to cut the egg-laying of beet armyworm moths by 75%.

Shorey expects his technique, designed to protect peach, walnut and other trees from codling moths and other pests, to be available for commercial use within a year.

For several years in the Sacramento Valley, Les Ehler, an entomologist at UC Davis, has been experimenting with ways to lure beneficial insects into sugar beet fields by providing food. Ladybugs, green lacewings and other insects that devour crop-munching pests need sustenance whenever those pests aren’t around.

Ehler has concocted food sprays of mixed sugar, molasses and yeast that mimic the nutritious nectar, pollen and “honeydew” (a sticky substance produced by aphids) that adult insects need for egg-laying.

The optimal formulation eludes Ehler, but he has hopes for solid versions of the goodies, which he has dubbed “power bars.” Ehler expects insects will be drawn to them.

“I can’t report spectacular success just yet,” he said, adding that, at its best, such a strategy would be only one tool used along with synthetic chemicals.

In his fields of citrus, avocados, pistachios, pears, tomatoes and other crops, grower George E. Myers has tried pheromone disruption and other methods with some success. But, facing the loss of several key synthetic chemicals in coming years, he decided that his agribusiness concern, Esperanza Ranches near Sacramento, needed more weapons.

Myers invested in AgraQuest and sits on its board. He said he is excited by the prospects for two promising natural-product fungicides in AgraQuest’s pipeline, both due on the market within two years. They are designed to control gray mold, brown rot, mildew and root rot--common afflictions in California’s fruit, nut and vegetable crops. Marrone, AgraQuest’s president and chief executive, projects that each product could eventually achieve sales of $50 million.

Three-year-old AgraQuest’s only commercial product to date is Laginex, used to kill mosquito larvae. The company’s scientists experiment continuously on promising fungi and bacteria contained in soil, lichen and other samples scoured from lake beds, forests, dunes and ocean caves.

Big chemical companies also are exploring the biocontrol trend--while making it clear that they believe synthetic chemicals are here to stay.

Dow AgroSciences, an Indianapolis-based unit of Dow Chemical Co., is eager to capitalize on its insecticide Success. It is expected to attract a following in California. Last year, it was used under an EPA exemption to control diamond-back moths in Salinas and other areas after growers were unable to solve the problem with the usual treatments.

“The new chemistries are fantastic,” said Bryan Stuart, government relations manager for Dow AgroSciences in Sacramento, “but that doesn’t diminish the importance of existing tools.”

Among those tools are advancements in genetic engineering. About half of the many USDA-approved biotechnology applications involve the development of plants that can tolerate herbicides, such as the Roundup Ready varieties from Monsanto Co. Pesticide makers have invested heavily in such technologies to ensure expanded sales of their proprietary chemicals.

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Also approved for commercial use in the United States are corn, cotton and potato crops that have been supplemented through gene manipulation with a soil bacterium called Bacillus thuringiensis, or Bt. The bacterium helps the plants naturally resist certain harmful pests.

But other solutions are needed, farmers and scientists agree. The research has lagged in large part because of a lack of public funding. Fewer than 10% of the 1,800 research scientists at the USDA’s Agricultural Research Service--and less than 10% of the service’s $745-million research budget--are focused on developing natural crop-protection methods.

“Enormous sums have gone to chemicals but dribs and drabs to biocontrol,” said Margaret Mellon, agriculture and biotech project director at the Union of Concerned Scientists, an environmental advocacy group based in Washington.

Sales of biopesticides as a group are growing faster than those of synthetics. Yet, says Marrone, “to be honest, nobody has made money on it so far.”

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Creating a Biopesticide

1. AgraQuest scientists (and their friends and relatives) gather samples of lichen (these pictures are from Florida), leaves, fruit, roots, dead insects and sponges from the sea. All of 19529987711702125932 2. The microbes grow on the dish, taking on different sizes, shapes and colors. Scientistswatch especially for a microbe that wards off another, creating a “zone of inhibition.”

3. Demonstrating the zone of inhibition, a microbe taken from a peach leaf fends off a disease that affects peach trees.

4. Using a fermentation “recipe” that coaxes the microbe to produce pesticides, scientists grow the microbe for two to five days.

5. Potentially pesticidal microbes are tested against a broad range of plant diseases (or insect pests) in 96-well plates. One microbe is tested in each vertical row.

6. Chemist Denise Manker uses a high-performance liquid chromatography machine to identify pesticidal components of the microbes. These are displayed graphically on a computer monitor.The peaks indicate properties that might prove to be strongly pesticidal.

7. AgraQuest President and Chief Executive Officer Pamela Marrone holds grape plants readyto be treated with one of the company’s biological microbial fungicides.

8. Microbiologist Lori Lehman works with fermentation, the fungicides will be sprayed on plants.