State’s Veterans of the Medfly Wars Draw a Bead on Encino Gypsy Moths

The state is well in control of gypsy moths found in Encino, agriculture officials say, thanks to California’s costly experience with the Mediterranean fruit fly several years ago.

A widespread system of traps set during the two-year Medfly infestation is credited for alerting the state to the moths, whose caterpillar larvae feed on leaves. Spraying will start this month in one of Encino’s lush hillside neighborhoods.

The effort is a far cry from the panic over the Medfly six years ago, when farmers lost tens of millions of dollars in crops and residents feared that aerial pesticide spraying would harm them.

Besides the traps, a meticulous border-inspection system, beefed up after the Medfly, has controlled the introduction of the moths into California, officials said.

“Our whole approach these days is the result of the Medfly situation,” said Gera Curry, a spokeswoman for the state Department of Food and Agriculture. “It was a bitter lesson to us, but a very good lesson.”

This month’s spraying is the result of trapping nine adult gypsy moths and finding four egg masses last year in the area around Skytop and Royal Oak roads in Encino.

Aerial spraying of a bacterial pesticide over 40 acres and the ground application of the chemical diflubenzuron, known by the trade name Dimilin, on nine properties in that area is expected to begin when the moth eggs, which are being watched in a laboratory, begin to hatch within a few weeks.

“By acting quickly, we not only save time and money and magnitude of the project, but think what we save with pesticides,” Curry said. “Why bombard the environment with many more tons of pesticides when we can snuff it out quickly at a lower cost?”

The Medfly cost farmers an estimated $73.7 million in unsold or damaged citrus and other crops, and it cost state and federal government nearly $100 million to eradicate.

State officials, who at the time had little experience in dealing with Medflies, had underestimated the insect’s ability to thrive in the cooler northern California climate, and because of an inadequate detection system, “we let it get ahead of us,” said Paul G. Engler, Los Angeles County agricultural commissioner.

During that effort, Medfly trapping was increased fivefold throughout the state, and gypsy-moth trapping was tripled in urban areas, Engler said.

The increased trapping is so that “once something does get into the state we find it a lot faster, and we can move on it a lot faster,” Curry said.

Statewide last year, 20 gypsy moths were caught in traps. There were 28 in 1985; 131 in 1984, and 60 in 1983. The traps snare the moths with a sexual lure.

The 16 border-inspection stations are the state’s first line of defense.

California’s border stations are regarded as the strictest in the nation, said Tom Flanigan, spokesman for the U.S. Department of Agriculture.

Fourteen of the stations operate around the clock all year to inspect cars, trucks, moving vans and recreational vehicles entering from areas infested with the gypsy moth or other pests, Curry said. The remaining two stations operate around the clock during the summer and 16 hours a day the rest of the year, she said.

The extended hours of operation were in response to the Medfly crisis.

Eggs Laid in Shade

At the border stations, inspectors examine vehicles’ undersides, which are favorite hiding places for gypsy moth egg masses. The female moth often attaches the eggs to the shaded undersides of almost anything stored outdoors, such as patio furniture or barbecue grills. A federal law in effect since 1983 requires people moving from infested areas to obtain a certificate showing that they are not carrying the gypsy moths.

The border stations arrange to have county authorities meet travelers without certificates--and some with certificates--at their California destinations, where the contents of trucks or moving vans are inspected, Engler said.

Vehicles found to have egg masses are steam-cleaned at the stations before they are allowed to enter the state. In the state’s 1985-1986 fiscal year, inspectors intercepted 365 vehicles infested with gypsy-moth eggs.

In 1985, the state began issuing citations to moving companies entering the state without certificates. In ‘86, the number of shipments with certificates increased from 20% to 95%, Curry said.

The cumulative effect of the state and federal measures “is starting to show,” Engler said.

Yet the persistence of the gypsy moths, which have defoliated millions of acres in the Northeast and Mid-Atlantic states and spread to the Midwest and Pacific Northwest, stands as a constant reminder of their potential to foil the agriculture department’s goal of keeping them out of California.

“The key thing will be how successful Washington and Oregon are,” said Don Henry, chief of pest detection and emergency projects for the state Department of Food and Agriculture.

‘Hitchhikers’

The Encino moths represent how the insect can slip through the state’s net. Those moths, it was discovered, “hitchhiked” into the state under the eaves of a child’s play house brought by a family who moved from Massachusetts in 1984, Curry said.

The Northeast was the center of most of the gypsy moth’s population peak in 1981, when 12.9 million acres of forest were defoliated, said Flanigan of the USDA.

The number was down to 1 million acres in 1985 but increased to 2.5 million last year, and “now it’s building up to the high point again,” he said.

As the gypsy-moth population in the Northeast moves toward another cyclical peak, the chance of more moths filtering into California has increased, Flanigan said.

Officials in Washington and Oregon, which also have been fighting the gypsy moth for seven years, said they are moving toward the moths’ eradication in their states. But, like California, each state faces potential reintroduction of the gypsy moth, and neither maintains border stations.

California officials might not be able to keep the moth out, Flanigan said, “but they can quickly nab it before it develops into a large-scale infestation.”

But officials’ ability to act quickly can be affected by environmental considerations. In what Henry described as “Oregon’s Medfly,” authorities there did not comprehend the seriousness of a gypsy-moth infestation until it had spread over 200,000 acres by 1984.

The state’s efforts to use carbaryl, a highly toxic chemical known by its trade name, Sevin, were delayed by environmentalists’ lawsuits, said Dalton Hobbs, a spokesman for the Oregon agriculture department.

Bacterial Agent Substituted

The delays forced the state to use a bacterial pesticide known as Bacillus thuringiensis or “B.t.” as its primary weapon against the moths.

Although Oregon officials had doubted B.t.’s effectiveness at first, the number of gypsy moths found in the state’s traps has dropped from 19,000 when treatments began in 1984 to less than 100 last year, Hobbs said.

In a lawsuit challenging California’s plans to use Sevin on gypsy moths in Santa Cruz County in 1985, a state judge ordered the agriculture department to use B.t.

The state picked B.t. to use in Encino because of its track record and because of fears that Sevin could threaten several residents’ backyard ponds of exotic fish, Henry said.

Dimilin, which is less toxic than Sevin, was chosen as well because officials were unsure that B.t., which must be applied meticulously, could eradicate the moth from the steep, heavily vegetated hillsides on its own, he said.

Citizens for a Better Environment, a California environmental group, has endorsed the use of B.t. Steve Dreistadt, the group’s pesticide specialist, asserted that eradication efforts using B.t. have succeeded elsewhere without Dimilin.

He said Dimilin breaks down into a potentially cancer-causing agent, but in the low dosages planned in Encino, “we don’t feel it poses a serious health hazard.”

The planned Encino spraying leaves the environmental group and the state in far more agreement than in 1984, when the group sued unsuccessfully to block the use of Sevin against gypsy moths in San Jose.

California’s agriculture department now prefers B.t. to Sevin, Henry said, mostly because of B.t.’s success. He also noted, “We’ve had good reception with it” from the public.

Although Henry and other agricultural officials would not rule out future use of Sevin, Engler said, “Why not use the less noxious material? . . . It doesn’t make sense to come in with a meat ax if a scalpel will do.”

Digestive System Attacked

B.t. attacks the insects’ digestive system, and is preferred by many environmentalists because it is deadly only to caterpillars and harms far fewer beneficial insects than Sevin or Dimilin, said Diane Baxter, staff scientist for the National Coalition Against the Misuse of Pesticides.

Nationwide last year, nine states tried to eradicate gypsy moths at 35 sites, and in all but five of the sites, B.t. was used as the primary pesticide, said Flanigan of the federal agriculture department.

Nevertheless, scientists continue to search for a more effective killer of the gypsy moth.

At the Boyce Thompson Institute for Plant Research at Cornell University, researchers are trying to find an explanation for the moths’ cyclical rise and decline in population. The sharp population declines, which occur as infestations peak, apparently are triggered by a virus the insect carries in a dormant state, said Alan Wood, a virologist at the institute.

Wood suspects the virus becomes active when the caterpillars experience stress, which apparently is brought on by having to compete with large numbers of other insects for a limited amount of food, or for food which is not on their normal diet, he said. Researchers are looking for a way to trigger the virus artificially, he said.