Changing Pesticide Use Poses New Challenges for Agriculture : Pest control: Increasingly resistant bugs and a lack of research funding are prime concerns, a new study says.

In just a few years, tomato growers across California have gone from being heavy pesticide junkies to moderate users. A couple years more and they could be nearly weaned from synthetic pesticides, says University of California professor John Trumble.

And, Trumble says, the use of more alternative methods of pest control can be done without sacrificing profitability. That’s important if the state is going to preserve the system that brings consumers the richest variety of high-quality, low-cost food in the world.

But California farmers’ ability to fend off crop-killing bugs, weeds, fungi and diseases may be in jeopardy.

“Consumers could soon find that California’s abundance can no longer be taken for granted,” warns a group of UC researchers in a comprehensive report, titled “Beyond Pesticides, Biological Approaches to Pest Management in California,” to be released this week.

Among the circumstances the report cites as troubling are:

* By the turn of the century, farmers will no longer be able to use many of the important chemicals they’ve relied upon for decades. About 150 pesticides will no longer be available, either because they’ve been banned or discontinued by their makers because of high costs of registering them under safety laws.

* At the same time, federal funding and farm support programs still discourage farming methods, such as crop rotations, that would rely less on use of traditional chemical pesticides. Similarly, commodity marketing groups’ rules, such as prescribing cosmetic appearance and size, encourage growers to use chemical pesticides.

* More and more pests are becoming immune to the pesticides that are available. Since 1984, “almost every major insect and mite pest in California has become resistant to at least one pesticide,” the report states.

* At university research centers and experimental stations, deepening budget cuts have left pared-down research staffs hard-pressed to keep finding new weapons against old bugs, while meeting the demands to respond to new invasions of virulent pests, such as the sweet potato whitefly. Last year, the whitefly cost more than $120 million in crop loss and again this year threatens to destroy winter vegetable crops.

“We’re beginning to mine a long line of work done in previous years, just as we’re losing the ability” to develop solutions for the future, says James M. Lyons, who helped bring together the study group that produced the report.

* Researchers are being forced to seek more outside funding, which favors research on crops of national and global significance, such as wheat and corn, rather than the cornucopia of specialty crops that together make up the bulk of California’s agriculture. Also, basic or fundamental research gets more funding than programs such as UC’s integrated pest management project, which puts the research to work in the fields.

“California is in deep, deep trouble,” says Milton N. Schroth, a UC Berkeley plant pathologist who was chair of the study group. “This is a state that gets a tremendous amount of money from agriculture and from exporting food materials. Where are we going to get the tax money, the money to take care of things, if our agriculture is destroyed?”

The report calls for an expanded program of research into biological pest management in five areas, including: development of plant varieties with built-in resistances to pests; the use of natural enemies to control pests, and the use of “semiochemicals,” such as mate-attracting pheromones.

These are among the most promising, yet controversial, areas of agricultural research today, and the state’s growing fields already are replete with successful examples of how science is capitalizing on nature’s amazing variety of problems and cures.

Tomato farming is one. Using a combination of biological controls and non-pesticide strategies, California tomato farmers have reduced the use of synthetic pesticides by nearly two-thirds. They have cut usage of insecticides--one form of pesticide--in half.

UC Riverside’s Trumble says that in the past, growers used to spray each crop as many 18 to 22 times, and several pesticides might be combined in each spray. Now, he says, commercial growers are only spraying their crops six to eight times, and usually with only one or two pesticides at a time. With continued research, especially with the microbial insecticide Bacillus thuringiensis (known as Bt), pesticide applications could be cut in half again, he says.

Trumble says tomato growers in Florida typically spray their crops 25 times, and in Mexico that can climb to as high as 35 applications of two to four pesticides.

Many forms of biological controls use nature’s own sense of balance to solve problems with weeds and insect pests. Among them are introduction of “good” bugs to neutralize “bad” ones.

For instance, walnut aphids used to cause severe damage to walnuts. Now, California walnut growers use a tiny wasp, Trioxys pallidus , to combat the aphids. The wasp is a natural parasitic enemy of the aphid; it lays its eggs inside the aphid and kills it. Researchers have developed a strain of the wasp that is more resistant to synthetic pesticides, so it can still be effective against the aphid when sprays are used to treat other problems.

But while the pressure is on agriculture to use such new tools to reduce its dependence on synthetic pesticides, the university’s approach is destined to draw criticism from many corners, including advocates of “sustainable agriculture,” who oppose use of any synthetic pesticides, and critics of genetic engineering, a basic technique in the development of many alternative pest control methods.

In the business sector, executives worry that university researchers are straying too far from basic science. “The university’s basic research and teaching missions get lost (when) more pest control guys are running around telling farmers what to do,” the head of one agricultural biotechnology company says.

Frank Zalom disagrees. He is statewide director of the UC Integrated Pest Management program in which researchers and growers interact to solve pest problems. Like Trumble, he points to success in the tomato fields.

“They are saving two insecticide sprays per year, on average, throughout state,” Zalom says. “That is due to the worm sampling program (initiated) by the IPM program. That’s about 800,000 acres worth of spraying (that’s not being done) . . . and it probably saved growers $12 million. Plus, there is less environmental harm and less exposure of workers.”

Zalom says the issues of pest management “haven’t gotten any smaller. If anything, they are bigger. Farmers don’t have the ability to use pesticides the way they did before. Pesticide makers have a harder time registering new materials. There are pesticide-resistance problems and more concern about food health and safety.”

While the issues have gotten more complicated, say researchers, funding has already declined 10% in the last two years. In the next year, most research programs face an additional 10% cut, and the IPM budget of $1.8 million may be slashed by 15%.

Lyons, who is director of UC’s Center for Pest Management Research and Extension, says the report catalogued research needs, and “the next step is to (assign) priorities, decide what to do first and where to focus resources.”

But what had been intended, in part, to be an eloquent plea for additional funding is looking more like an elegy. Research planning is in a quandary, Lyons says. “The system is coming apart. We see what is not happening in Sacramento, what our budgets might look like with even bigger cuts . . . and it seems like a moot point to prioritize spending when we’re faced with making decisions about layoffs and just trying to keep the ship afloat.”