How the Bugs Finally Won : For 22 Years, the Cotton Farmers of the Imperial Valley Waged Chemical Warfare Against ‘Pinkie.’ This Summer, They Were Forced to Find Another Way.

EVERYTHING SEEMED NORMAL in the Imperial Valley’s farming communities. But in the fields, millions of pink bollworms were shedding their cocoons . Mutant survivors of more than two decades of chemical warfare, they would emerge from the soil with the arrival of spring. And each month this summer a new generation, larger and more resistant than the last, would swarm over the fields in a reproductive frenzy. As the season wore on, leaf hoppers and lygus, stinkbugs and spider mites would swell the insect army. It was time for cotton farmers to prepare for battle. Fewer than 17,000 acres of cotton remain of the 143,000 planted a decade ago. Only growers with a defensive strategy could expect to survive the onslaught that would come with the night heat of September.

IT WAS 10 MINUTES SHY OF NOON on a Friday in early May but the temperature already was climbing toward 100 when John Benson pulled up to the Stockmen’s Club. Whether measured by the acreage he owns or by his girth, “Big John” is one of the largest growers in the valley. Since taking over from his father in 1964, he has nearly doubled the size of the family farm. No amount of hard work, however, seemed to improve his cotton yield. Only 600 acres of cotton remain, and if past experience is any indication that too is in peril.

Benson skirted the hissing sprinklers and strode toward the entrance where Clyde Shields was waiting. In the lexicon of the Imperial Valley, Shields is a “bug man,” a free-lance entomologist who advises growers when and what to spray on their crops. The two men have been fighting the pink bollworm for 20 years. Shields has the entire history of the conflict on computer. He can predict the exact day the worms will hit. He knows the kill ratio of every pesticide. His temperature and infestation graphs cover dozens of cotton fields. Unfortunately, all the data indicates that the battle between vertebrates and arthropods is being won by the bugs.

“ ‘Bout time for pinkie to come out of the ground,” Shields said by way of salutation.

“Hell, it’s already a zoo out there,” Benson scowled, jerking open the door. “By September pinkie will be like the Chinese army in North Korea.”

Big John and the bug man strolled past the gallery of mounted steer heads and took a corner table in the dining room. They were midway through their salads when Shields pulled a sawtooth-shaped graph from his pocket. “Look at these infestation projections,” he urged. “I think we can keep our loss below 10% if we limit spraying to the temperature peaks. If we spray any more during a long season, we’ll have a resistance problem for sure--and risk killing all the beneficials.”

Big John momentarily pondered the dilemma. If he didn’t spray enough, the pink bollworm would take most of his cotton. Too heavy an application, on the other hand, would further upset the predator balance, leaving the cotton vulnerable to a host of other, equally voracious pests. A former Navy officer and graduate of UCLA Law School, Benson drained his iced tea, then looked directly at Shields.

“I can accept losing my melons to a root fungus, because that’s one of the risks in this game,” he said, rolling a toothpick to the corner of his mouth. “But I can’t stand to lose any crop to a bug. It’s just a matter of pride.

“It’s the destiny of this valley to grow cotton. I’ve got plenty of water, some fairly decent soil and all the sunshine in the world. The only thing standing between me and prosperity is the damn pinkie.”

“So the strategy is--”

“Scorched earth,” snapped Benson, rising from the table. “We zap pinkie now so he can’t nail us in July. Fog it in there, Clyde, before every female moth out there becomes the great-grandmother of 400,000 more pinkies.”

THE IMPERIAL VALLEY IS ONE of the richest agricultural areas in North America. Though it annually receives less than three inches of rain, irrigation water from the Colorado River allows crops to grow year-round. There are no tule fogs or thunderstorms like those that plague the San Joaquin and Sacramento valleys. It is a bowl-shaped, 500,000-acre greenhouse filled with fine-textured silt a mile deep in many places.

For more than half a century farmers grew rich growing cotton. Extra months of cultivation meant cotton plants could be picked twice, boosting yields far above those possible elsewhere in California. Even after DDT was banned in 1962, farmers continued to average more than three bales an acre. Then one late summer day in 1965 the pink bollworm floated in from Arizona, and the good times ended.

The first cotton fields hit were near Cat Tail Wash outside Calipatria. Benson and Shields piled into their pickups and drove up to assess the new adversary. “It was a terrible thing to see,” says Shields. “Every boll in the field was full of worms.” Big John knew he had made an enemy for life. “They were bright pink with little brown heads,” Benson says, “and when we cracked the bolls open they reared up and just stared back, defiant. Pinkie was the ugliest thing I’d ever seen.”

The pink bollworm is difficult to kill because it’s seldom exposed. The female moth lays her eggs under the leaves that wrap around the infant boll. After hatching, the worm immediately bores into the boll, which, like the leaf under which the egg was placed, provides shelter from insecticides. After two weeks of feasting inside the boll, the worm--now bright pink and half an inch long--spools to the ground and burrows in for a brief snooze. Five days later the pupa surfaces in the form of a moth that will spend its remaining days mating indiscriminately and laying 300 eggs. The final phase of the bollworm’s life is the only time it’s ever vulnerable and by then the damage is done.

Egypt’s Pharaohs tried--unsuccessfully--to kill the pink bollworm by dusting their cotton with arsenic. Imperial’s agribusinessmen were confident a nice organophosphate would do the job. Scientists from UC Riverside urged a different approach. Only the sixth generation of pink bollworm was genetically capable of hibernating in the soil all winter. If farmers picked cotton early and plowed their fields, there would be no cotton for that generation to eat. The insect’s life cycle could be broken, they reasoned, if farmers accepted lower yields and reduced profits.

The academicians were politely thanked for their advice, then escorted to the county line. Men who had tapped the mighty Colorado, coaxed life from an alkaline desert and then bought beach condos in La Jolla were not about to compromise with a worm. A delegation was sent to Sacramento, where state officials agreed to underwrite the cost of a valleywide application of pesticides.

“The University of California told us how devastating the pink bollworm would be, but nobody was impressed by what they had to say,” Benson explains. “We thought we could kill the worm before it became resistant. We had every reason to be optimistic. We’d beaten every adversary until pinkie arrived.”

Challenging nature is part of California’s ethos. Los Angeles and San Francisco are great metropolises today in part because engineers were able to tame and transfer water from the Owens and Hetch Hetchy valleys. It was with similar confidence that land developers in 1901 cut the bank of the Colorado River to channel irrigation water down into a mesquite-choked desert known as the Salton Sink.

Unfortunately, nature fought back in the renamed Imperial Valley. By the summer of 1904, silt was starting to plug the main irrigation canal and farmers were getting nervous. To assure continued irrigation, a second cut was made in the river bank. But when spring floods hit the following year, the weakened embankment collapsed, sending the entire flow of the Colorado roaring into the basin down to the Salton Sink.

Neither the state nor the federal government would assume responsibility for the flooding. In desperation valley growers turned to E. H. Harriman, wealthy president of the Southern Pacific. With a budget of $3 million and help from six Indian tribes, Harriman sent flatcars of rock into the breach. By February, 1907, his engineers had managed to patch the bank, but not before the Colorado had turned the Salton Sink into a sea 50 miles long and 15 miles wide.

By 1967 the farmers’ eradication campaign had produced an ecological imbalance. Pesticides that had kept fields immaculate the previous year began to fail. Instead of five applications, eight were required. Chemicals that wiped out pink bollworms seemed to whet the appetite of spider mites, who began sucking the chlorophyll from cotton fields they’d never visited before. As spraying increased, so did casualties among beneficial insects. Pesticide intended for mites zapped all the honeybees. For the first time in memory agricultural revenues faltered, for without pollination from bees, melon and seed crops couldn’t propagate.

The following year crop-dusters flew at night, when bees trucked in from Fresno were asleep in their hives. But that precaution didn’t save wasps that had previously kept the cotton-leaf perforator in check by feeding on its eggs. Free of their traditional enemy, perforators ate holes in leaves not blotched by the mites.

Cotton growers mixed pesticides, and the number of applications mounted to 18. The pink bollworm kept on eating. By now most of the tiny insects that kept nature’s balance were gone, paving the way for the arrival of the tobacco budworm, which likes to wiggle its tail outside the boll while it munches with fang-shaped jaws on the cotton inside.

Temperature, rainfall and the pattern of crop rotation all affect insect populations. A certain combination of pesticides that fails one year will leave fields spotless the next. But eventually the bollworm always counterattacks.

Earlier this summer, entomologist Tom Miller feared that the final battle was approaching when he was presented with a pinkie that wouldn’t die. The trap from which it was hanging had enough poison on it to ensure instant death. Yet here was this moth, its antennae erect and abdomen firm, still struggling after two days.

For seven years the 47-year-old UC Riverside insect neurophysiologist has been seeking a solution to the problem of pesticide resistance. Aided by rural chemical salesmen, who place traps containing differing amounts of insecticide in the fields for which they are responsible, he can measure the rate at which successive generations of insects acquire toxic immunity. It is a sort of early-warning system, and on this mid-June morning in the PureGro Chemicals office it was flashing emergency red.

“The numbers are staggering,” drawled Richard Wellman, a lanky pesticide salesman. “I’ve sampled a half dozen places in the south end of the valley, and in each one I’m facing field failure.”

“You’ve definitely got a lot of resistant genes out there,” Miller observed as his eyes skipped down the columns of statistics. Wellman was using three times more insecticide than in 1986, yet killing less than 40% of the pinkies. He could get rid of all the worms if he increased spraying by a factor of 20, Miller calculated, but at that point insecticide would be literally dripping from cotton that would no longer be economical to produce.

Miller didn’t have a solution to Wellman’s problem, but perhaps Clyde Shields would know what to do. Certainly he needed to be warned that the new generation of pink bollworms on the way was more resistant than previously imagined. Miller thanked Wellman for the information and quickly headed south. The resistance ratios were the worst he’d ever seen. In human terms, it was as though a grower who had taken two aspirins for last year’s headache now needed 100,000 aspirins. If things were this bad at Palo Verde, they would be worse in Imperial where resistance was a greater problem.

For more than 40 years entomologists have searched for the perfect pesticide--”the silver bullet,” an appropriate euphemism given the quixotic nature of the quest. Though dozens of vertebrate species have disappeared off the face of the Earth, not a single insect has ever been eradicated by man.

Because arthropods don’t have a cardiovascular system or lungs like vertebrates, they are nearly impossible to poison or asphyxiate. The central nervous system is their one vulnerable area. For this reason the goal of most pesticides is to disrupt nerve impulses, leaving the paralyzed insect to die from dehydration or to be eaten by predators.

An insect is genetically programmed to survive and reproduce, and time is always on its side. A human generation lasts 25 years; pink bollworms reproduce every 24 days. Even a pesticide that wipes out 99% of an insect population compounds the problem, since the 1% with genes that allow them to survive immediately produce enzymes that make their offspring more resistant. Of the 490 insects resistant to chemical pesticides, 100 can be found in California.

It was not until 1970, when pink bollworms began appearing in the southern San Joaquin Valley, that the California Cotton Pest Control Board seriously began to study alternatives to pesticides. Eventually, it decided to turn the bollworm’s greatest tactical advantage--fecundity--against it by creating a barrier of infertility between

Bakersfield and the Salton Sea. The key to the plan’s success was a constant supply of millions of sterile moths.

“MORE EGGS!”THE ORDER comes down the assembly line in relays. “More eggs!” A young woman in the scrub room immediately grabs two beakers and hurries out the door. Fred Stewart, an insect pathologist in charge of the U.S. Department of Agriculture’s pink-bollworm-rearing facility in Phoenix, observes it all and smiles. “The greatest thing an entomologist can do is to eradicate a pest insect,” he says. “California may be talking suppression, but my goal is extinction.”

Pinkie’s demise is Stewart’s profession and passion. For him pinkie is not only “an alien intruder,” but also “a friend with weak spots I must never underestimate.” Seven days a week, 165 days of the year, Stewart, 46, sends 4.8 million sterile moths to California. Dropped over the Coachella Valley at dawn and across the southern San Joaquin the following day, the moths “are my agents who must rise up each night and mate” with their fertile rural cousins.

It’s definitely a love-hate relationship. He nurtures the young larvae on a diet of wheat germ and soy flour, makes sure the 5.5 million pupae on hand every day have a warm place to sleep. His moths are sheltered from the Arizona heat in air-conditioned warehouses. Then, when they’re 3 weeks old, Stewart slaps them in cans--125,000 at a time--for a 20,000-kilorad jolt of cobalt 60. Last year, the USDA facility produced 702 million sterile pinkies.

The USDA program prevents the pink bollworm from marching up the San Joaquin, but in the Coachella Valley the infestation continues. Radiation that leaves the moths sterile also diminishes their libido. Instead of homing in on randy females, the airborne moths flutter about ambivalently.

In the Imperial Valley, where the per-acre pinkie population in late summer averages about 150,000, at least 30 million sterile moths would be needed each day to check the bollworm’s proliferation. Since producing this many steriles would be impractical, growers have continued to spray. But instead of resulting in higher yields, the extra applications only killed more beneficial insects, creating even greater opportunities for more cotton pests.

In 1977, the bollworm and its allies attacked in unison. One desperate group of farmers chartered a plane and flew to Louisiana, where pesticides more toxic than those allowed in California were still on sale, but just as they were being applied hurricane rains swept up from the Gulf. Subsequent sprayings were invariably followed by showers, and by the end of the summer many farmers had lost their entire crop. “The budworms hanging from the bolls seemed as big as snakes,” Benson recalls. “I’d walk out of a field and a hundred of them would be hanging from my clothes.”

By 1981 the list of preferred pesticides--Ammo, Pounce, Lasso, Karate and a toxic bacillus called Javelin--were losing their effectiveness. Pilots who went aloft at night flew through insect clouds as dense as fog. Nothing seemed to kill the pink bollworm--or another, newly resistant pest, the whitefly, which deposits a sticky excrement called “honeydew,” as well as 70 different viruses, on every crop it touches. A kiss from the whitefly stunts tomatoes, causes squash leaves to curl and drains beets of their sugar. No longer was declining productivity limited to cotton farmers. Between 1979 and 1982 the valley’s agricultural output dropped $75 million, to $762 million.

In 1982 the whitefly returned in even greater numbers. What alarmed farmers most, however, was a disturbing mutation. Repeated exposure to pyrethroids, an insecticide made from chrysanthemums, had somehow left the insect’s feet coated with a waxy substance that allowed it to skate across plants doused with insecticide. Desperate pest-control advisers combined more than a dozen different chemicals into a toxic witches’ brew, but it had the effect of a gentle summer shower. “It was the worst year of the war, and a lot of people figured it was time to get out,” says Benson. “The animals finally had taken over the zoo.”

THE ONLY LIGHT ON THE horizon in 1982 came from Phoenix, where USDA entomologists thought that they finally might have discovered the silver bullet. Several years before, scientists at UC Riverside had synthesized the sex hormone, called pheromone, that the female pink bollworm uses to attract her mates. The discovery prompted detailed studies of pink bollworm sex. Graduate students carried infrared lights and “mating tables” out to the fields so their professors could observe the moths’ nighttime mating ritual. The reports were wildly enthusiastic. When released in sufficient amounts, pheromone was nothing less than an irresistible aphrodisiac. If a field smelled of bollworm pheromone, moths didn’t bother to find appropriate partners. Twigs, clods of dirt, fallen leaves all became objects of sexual embrace.

The success of pheromones marketed under names like Disrupt and No Mate, though, has been limited by their cost--about five times more than conventional pesticides--and pinkie’s continuing unpredictability. The silver bullet that works on some fields misfires on others. Pheromone “ropes” tied in high cotton sometimes send pinkie diving for the dirt. If placed near the ground, moths couple in the air. One study seems to indicate that a few females are blasting through the synthetic pheromone cloud by somehow emitting hormones that are even more pungent. If true, it is a nightmare few scientists dare contemplate.

LARRY GILBERT, cotton farmer, stood alone in front of his peers on a blistering midsummer morning, a man unaccustomed to public speaking. “I never used insecticide,” he admitted somberly, “until the pink boll worm arrived. Then we sprayed, but it just ate more. When we sprayed again, its appetite increased. My acreage and profits are down. We’ve got to break the life cycle of this insect.”

None of the men silently studying their scuffed boots liked Gilbert’s message, but neither could they deny its truth. The economy of the entire county was in jeopardy. Since 1979, the valley’s gross agricultural income has fallen 18%. Among California’s 58 counties, Imperial ranks dead last in median family income. Unemployment stands at 31%. The non-agricultural economy is stagnant. Per capita savings in Imperial’s banks is one-fifth the state average. Even the venerable Planters Hotel in Brawley has closed.

Plowing under plants still able to produce cotton is painful for a farmer. Admitting defeat in a war with a bug is perhaps even more difficult. But Imperial’s cotton growers had no alternatives this summer when they assembled in El Centro to reconsider the shorter growing season they had airily rejected 22 years before.

One after another, farmers took their turns at the podium in the front of the Imperial Irrigation District auditorium. Prosperous growers pushed hard for the shorter season. If the valley’s ecological balance was restored, they argued, higher profits from vegetable crops would more than offset reduced cotton revenues. Owners of smaller farms near the Salton Sea rejected that logic. Their less fertile land was better suited to cotton than top-dollar produce. For them the cotton that grew during the last six weeks of the season was the difference between profit and bankruptcy.

“We won’t be able to compete with either Mexicali or Arizona if we start changing the rules,” argued Charles Smith Jr. “I say our only chance of survival is to keep on fighting pinkie.”

“I don’t see how you can make a profit,” replied Don Cox, the valley’s most efficient cotton producer. “Twenty-five percent of my expense already goes for pesticide.”

The debate raged through the morning. Experts from the federal government and the University of California presented a numbing array of statistics, all of which were ignored. When John Benson’s turn finally came, the room fell silent.

“We’re all farmers here,” Big John began, “and we all know that we’re on a pesticide treadmill.” Grasping the podium, he leaned forward and, in a voice worthy of an Old Testament prophet, urged his neighbors to repent. “It’s the chemicals,” he shouted. “With all our chemicals it still gets worse every year. . . .

“We all want to be rich and famous cotton growers, but all our margin is going to the chemical companies,” he concluded with a flourish. “Insecticides are destroying the valley’s industry.”

The overwhelming vote in favor of an abbreviated growing season may have come 22 years too late, but it was welcomed nonetheless by entomologists, who characterize the recent decision as courageous. “It’s a dramatic move that gets the valley on a path back to better times,” says Thomas Henneberry, director of the USDA’s Western Cotton Research Laboratory. “This is not a new technology or another restriction, but a major overhaul in the pest-management system. For years these farmers have concentrated all their efforts on maximum yield. Now they’re focusing on optimum productivity. That’s a radical step.”

The war against bugs will never end, entomologists say. There will be other bugs, other battles. “You have to be impressed by what the pink bollworm was able to survive,” concludes Tom Miller. “The problem with pinkie may be over, but the boll weevil is waiting in Arizona.”