UC Entomologists Do Battle With Pesky Array of Bugs

Professor Michael Rust is clearly a man accustomed to bugs. With extraordinary nonchalance one recent day, the scientist tapped on the shell of a 3-inch-long Madagascar cockroach clinging tenaciously to his finger.

Rust was attempting a scientific demonstration--getting the wriggling pest to hiss. A curious if squeamish visitor was waiting expectantly in a corner some eight feet away, but the featured insect seemed in no mood to cooperate.

Suddenly, there was a noise--a whoosh, like a bicycle tire just punctured--as the bug obligingly expelled air through her abdomen.

“There she goes,” Rust said proudly as the ghastly roach wiggled its antennae and crawled toward his wrist. “Listen to that. Quite a loud one,” he beamed.

Cockroaches, fleas, houseflies, termites--these are the prized inhabitants of Professor Rust’s urban pest laboratory on the University of California campus here. A short walk away, colleague Thomas Baker studies crop-eating moths in hopes of devising ways to disrupt their mating habits.

And in another building, scientists specializing in biological control are rearing parasitic wasps to be deployed against a stubborn pest that threatens the state’s valuable nursery and citrus industries.

These are busy times for entomologists, especially those in Southern California.

The Mediterranean fruit fly continues to pop up around the Southland, prompting aerial spraying of malathion to squelch the invasion before the bugs lay waste to the state’s multimillion-dollar agricultural industry.

Another pest, the ash whitefly, already has defoliated hundreds of shade trees and spoiled innumerable back yard barbecues, and scientists fear it is poised to attack nursery and citrus crops next.

Meanwhile, the Africanized bee--often called the “killer bee” because of its nasty temperament--is expected to invade California in three to five years, a forecast that has researchers hunting for ways to control the easily agitated insect.

And at least one case of Lyme disease--which is common on the East Coast and is spread through tick bites--has been documented in this region.

So, not surprisingly, the entomology laboratories at UC Riverside are abuzz with activity these days.

“It’s an exciting time for us,” said Baker, chairman of the department. “Our mission--which is to improve the quality of life for Californians--is more demanding than ever.”

Regarded as among the top five in the country, Riverside’s entomology department was born even before the University of California formally opened a branch here in 1954.

Like several other campuses, the Riverside school grew out of a state-funded agricultural experiment station, launched in 1907 to aid the region’s booming citrus industry. From the start, pest management was an integral part of that effort.

Entomologists in Riverside quickly made a name for themselves in a number of fields, most notably, biological control--the science of managing a pest through the use of its natural enemies.

“Historically, Riverside was the home of biological control,” said Edward Sylvester, an associate dean of UC Berkeley’s College of Natural Resources and former chairman of its department of entomological sciences. “Some of their people were pioneers . . . and can take credit for big successes.”

In part due to discoveries at UC Riverside, for example, many major citrus pests in Southern California are effectively managed through the deployment of their natural predators and parasites, thereby reducing pesticide applications by millions of tons through the years.

Today, two UC Riverside scientists are leading perhaps the most widely watched biological control effort in the state--the battle against the ash whitefly.

The pesky insect, first spotted in California in August, 1988, at a Van Nuys fruit stand, has multiplied rapidly, infesting trees from the Mexican border to Sacramento. The pinhead-sized bugs--which are not native to North America and thus had no natural enemies here--suck the fluids out of a tree’s leaves, stripping it of foliage, and deposit a sticky ooze that discolors fruit, stains patios and ruins automobile paint.

With help from the California Department of Food and Agriculture, Riverside professors Tim Paine and Thomas Bellows have imported eight species of parasitic wasps and predatory beetles they hope will curb whitefly populations before extensive harm is done to the state’s valuable nursery and citrus crops. The first batch of wasps--which do not sting humans and look like specks of dust--will be set free Friday in the San Fernando Valley.

Another UCR researcher, Robert Luck, successfully imported a wasp from Georgia to attack the Nantucket pine tip moth. The moth bores into the needles of Monterey pines, leaving them looking “like somebody took a blowtorch to them,” Luck said. While the wasp has “done the trick” in San Diego and Orange counties, its effectiveness in inland areas is still in question, he said.

As for the troublesome Medfly, virtually no research on that pest has been done at UCR because of state regulations forbidding its importation, even for research. Nearly all Medfly studies take place in Hawaii where the insect is endemic.

By the chairman’s account, UCR also is on “the cutting edge” in research to identify diseases that afflict pests and use those pathogens to control the bugs. Genetic engineering has helped scientists develop insecticides made of these disease organisms to attack mosquitoes, black flies and moth larvae.

Other pioneering work includes the study of “pheromones”--the blend of chemicals a female insect emits to attract a male. One method of monitoring pest populations is to create a replica of that sex-attracting scent and place it in traps. The first pheromone registered for commercial use was developed at UCR.

More recently, pheromone research has focused on using the nontoxic chemicals to interrupt mating, particularly with the pink bollworm moth--a cotton pest--and the Oriental fruit moth, which munches on peaches.

“You spray just a few grams per acre over a crop and the males simply can’t find the females. They become totally confused,” Baker said. “You can disrupt mating for weeks. Eventually the pests die off and the crop is saved.”

Baker’s research focuses on the behavior of moths as they respond to the scent. Using a fiberglass wind tunnel in his laboratory, the scientist watches the insects as they zig and zag in a desperate search for the female.

“I’m trying to figure out how moths smell and orient themselves as they respond to these pheromones,” Baker said as he moved his head to and fro in imitation of his winged subjects. Not only will such work help farmers battle pest infestations, it may also “teach us something about olfaction (the act of smelling),” he predicted.

“That’s the beauty of entomology,” said Baker, whose interest in pests began with boyhood butterfly collecting. “If you’re lucky, you add to basic knowledge and can also see the practical effect of your work in the field.”

Not far from Baker’s lab, Rust is directing his talents at urban pests. Long neglected by entomologists, this area is becoming increasingly important as agriculture declines and more people congregate in cities. In recognition of this trend, UC Riverside recently increased the number of urban pest positions on its 45-member entomology faculty.

To some, Rust might have the most loathsome of jobs. The soft-spoken, affable professor concedes he rarely becomes attached to his specimens: “You can’t exactly put them on a leash.”

But he takes pleasure in knowing that his work might benefit an aggravated homeowner fighting termites or a hospital administrator frustrated by an army of cockroaches. Also, he notes, termites cause $390 million in damage annually in California; they are no minor problem.

“Our clients are people, not some crop out in the field,” he said. “California is one of the most urbanized areas in the world, with 93% of the people on 6% of the land. And along with urban living comes pests.”

Rust’s laboratory is no place for the timid. A foul smell hangs in the air, and wherever one looks there lurks a jar or bin or vial teeming with menacing insects. Graduate students sprint here and there, some holding tubes of flea-infested carpeting material, others carrying dog chow to the hungry denizens of the Roach Room.

To support his research, Rust must raise huge numbers of cockroaches, 25 species of them. This is done in plastic garbage cans in warm, humid chambers behind his lab. An electronic barrier around the rim of the cans keeps the roaches from escaping. Unless something goes wrong.

“We did have a crisis once, when the barriers failed,” Rust recalled. “The roaches learn very quickly. They all escaped.”

How many? “Over a million of them. It took us a year to recover” and get research back on track.

Chris Levine is the lab assistant in charge of roach rearing. She sometimes spends an entire day doing nothing but plucking roaches from the garbage bins and sorting them by sex. Other times she is out in the field, collecting the bugs from apartment buildings, fine restaurants, hospitals.

“Insects are interesting, but it’s a real pain when they get out,” Levine said.

The hissing Madagascar roaches are the lab’s special attraction. While of little research value, the bugs’ sheer size make them intriguing, and they’re always a hit with visiting schoolchildren.

“They’re definitely the show-stoppers,” Rust said recently as he picked through a bin of the crawling monsters in search of a perfect specimen.

They are also extremely docile, which makes them of great value to filmmakers. Eight thousand of the Madagascar roaches were shipped from Riverside to England for the filming of “Indiana Jones and the Temple of Doom.”

Among the challenges facing urban pest experts? While pesticides usually have short-term effectiveness, heavy usage through the years has enabled pests like ants, roaches and termites to build up resistance to many products. Also, many of today’s consumers are reluctant to use chemicals because of health or environmental concerns.

The challenge, then, is to find less-toxic products or other ways to keep roaches and other insects from setting up camp in places they’re not wanted. Several years back, Rust and two colleagues discovered a fungus thought to cause a deadly cockroach disease. They published their findings, and hopes were high that a safe means for treating the pest had been found.

But science has its perils, and the miracle fungus was lost after it was eaten by mites. Scientists have so far been unable to reestablish it.

Meanwhile, Rust has turned his attention to a new project, funded by a $100,000 grant from the Getty Conservation Institute. The goal of the research is to kill termites and other insects that infest artwork and artifacts. Researchers hope that by using inert gases to remove oxygen from a treatment chamber, they could suffocate the insects.

“Wooden frames, baskets, fabrics, stuffed birds and animals--all are susceptible to attack,” Rust said. “We want a nonchemical way to treat these pieces so their integrity is not threatened.”