Alien Invaders of the Bug Kind : L.A. County is infested with the ash whitefly, a native of Europe and a threat to agriculture, but there is no money to fight the pest.

Times Staff Writer

The first call came from the owner of a Van Nuys vegetable stand.

Mysterious white insects, Felix Tapia told authorities, were invading his property. They were flitting around his ash trees, creating a nuisance that was interfering with business.

"I knew they weren't aphids, you know, I'd have recognized them right away," Tapia said last week, recalling last summer's incident. "I didn't know what they were. And there were just so many of them."

By the time the confounding creatures were identified three weeks later as Siphoninus phillyrea --a species commonly found in Southern Europe and the Middle East--the pests had multiplied exponentially. So too had phone calls from homeowners throughout Los Angeles to the county agricultural commissioner's office in El Monte--3,000 within six weeks.

Authorities still don't know how the insects, dubbed ash whiteflies by the state pest control scientists who identified them, made it past importation inspectors. Nor do they know exactly how to counterattack in a battle that probably will have several fronts.

No Known Natural Enemies

On one side are the tiny leaf-sucking pests, which have no known natural enemies in California, are difficult to kill with chemicals and multiply with lightning speed. There are now billions and billions of the creatures, which eventually could cause severe crop damage.

On the other side are government scientists who, hampered by severe budgetary constraints, are fighting back in what, by comparison, seems like geologic time. With no money now available to send researchers to Europe to identify and bring back natural enemies of the insect, authorities say they cannot even begin attacking the problem until the next fiscal year begins in July.

As spring approaches, authorities are bracing for a new barrage of complaints from homeowners, who have reported swarms of the insect lodged on the leaves of dozens of varieties of trees in the rose, olive and legume families--groupings that include pear, apple, apricot, pomegranate, olive, plum and peach trees.

Bob Atkins, deputy agricultural commissioner for pest prevention, is the county's four-star general in the battle against insect invaders.

Most of the million-plus types of insects found in Los Angeles County, he says, are kept in check by the delicate balance of nature. But when species with no natural predators or parasites are introduced--generally through imported flowers, fruits or vegetables--that means war.

Not Like Medfly

The new nemesis, he says, differs significantly from the Mediterranean fruit fly, which is susceptible to pesticides and can also be fought biologically with the release of millions of sterile male flies.

While the Medfly, which preys on more than 260 types of crops, is like a cancer, Atkins says, the ash whitefly, which weakens some three dozen types of trees by sucking the juices out of their leaves, is more like a low-grade virus.

"They cause a constant lack of vigor in plants. It's just like having a bunch of ticks sucking your blood," Atkins says.

The whiteflies also excrete a sweet, sticky honeydew that attracts ants and results in the formation of a mold.

Last August, when county officials responded to Tapia's initial report, they were stumped by what they saw.

The reason, it turned out, was that the ash whitefly, which at this point is most predominant in ash and ornamental pear trees, had never before been encountered in the Western Hemisphere.

In Sacramento, where dead flies were mailed, state Department of Food and Agriculture entomologist Ray Gill made a positive identification.

Gill also conducted further research. His findings were unsettling.

Unlike Medflies, which are lured by sweet baits laced with the pesticide malathion, ash whiteflies are not interested in much of anything besides sucking on the underside of leaves. Moreover, the whiteflies, which likely arrived by boat or plane within the last two years, have spread so rapidly that insecticides would almost certainly prove futile.

"Every corner of Los Angeles County is infested," Atkins said. "It's too far gone."

Research also revealed a potential long-range menace, due to the insect's hardy nature.

The ash whitefly, relatively dormant during cooler months, reproduces as many as four to five times a year, with the female laying about 200 eggs each. Moreover, the insect, which commonly ranges from Ireland south to Ethiopia, appears capable of surviving in a wide range of climates.

Other Spottings

Within a few weeks of the Van Nuys sighting, the pest had also been spotted in Orange and San Diego counties. It stands to reason, experts say, that the ash whitefly will eventually "hitchhike" on leaves that fall on cars or clothes, to the fertile, sometimes cooler, San Joaquin Valley. There, the experts say, the insect is likely to attack olive, apple, pear and peach trees, among others.

"The potential problems are quite serious for California, indeed for the nation," UC Riverside entomology expert Tom Bellows said.

Or as County Agricultural Commissioner E. Leon Spaugy put it: "They haven't made the Walk of Fame yet, but they are on their way."

For now, the chief concern of agricultural officials is that Los Angeles County's $153-million-a-year nursery business would suffer economic catastrophe if quarantines were imposed by other states. While pesticides are deemed futile on a mass scale, they say, the controlled use of chemicals, which the ash whiteflies would ingest when they attack a plant, has thus far proven effective on a plant-by-plant basis in nurseries.

Biological Response

The only long-range solution, authorities add, is the introduction of a natural predator or parasite that will keep the whitefly in check without causing environmental damage of its own.

State and federal permits to introduce such controls have already been received, Bellows says, and two likely candidates are under consideration. They are a tiny type of ladybug and a miniature species of wasp with a body the size of a pinhead.

But there is a major obstacle--money.

Bellows estimates that an effective biological control program would cost approximately $500,000 over five years. Until last week, the only commitment had been $10,000 from the Los Angeles County Board of Supervisors.

"We have the permits and we're ready to fly but we haven't got an airplane ticket yet," Bellows says. "I'm embarrassed to suggest that, right now, neither the interventive nor the research arm of the state are able to do a great deal of work. . . . The long and the short of it is that we need to get to Europe and need a staff to rear colonies and natural enemies to spread them around Southern California. That takes people and real dollars."

Another $10,000

Following a summit meeting this month between representatives of county agriculture commissioners and the state Department of Food and Agriculture, state officials announced that they would add another $10,000 to the pot--as of July.

"Nobody has money this year, everybody is hurting, our budget here is in tremendously bad shape," said Gera Curry, a spokeswoman for the state Agriculture Department. "This will be enough to get researchers over to Europe and North Africa to at least start working."

"We're not going to have a solution at best until a couple years down the road anyhow," she added. "Unfortunately, homeowners should not look for any quick relief."

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