Money Needed to Fight the Ash Whitefly

Last fall’s biological warfare experiment against the ash whitefly, which has attacked trees in at least 15 California counties, was successful in killing the destructive pests, researchers reported Monday.

However, ash whitefly experts said they need more money to continue the research that could provide a long-term solution to the ash whitefly problem.

“We could really be set back if the University of California was unable to continue its research,” said Peter J. Stoddard, statewide coordinator for the Department of Food and Agriculture’s ash whitefly project. “It’s kind of hard to keep ahead of this insect.”

Agriculture departments throughout Southern California, including Orange County’s, have funded the research. But agricultural commissioners said funding also needs to come from other parts of California because the problem has become statewide.

Gilbert Resendez, a Southern California spokesman for the Nursery Growers Assn. of California, said his group plans to lobby state legislators for additional support. “It’s really important to our industry,” he said.

The fight against the ash whitefly is being waged with imported parasitic wasps, one of the whitefly’s natural enemies. About 300 wasps were dispersed in small groups last fall.

The wasps destroy the fly either by attacking it or implanting it with eggs that consume the fly from the inside out as the egg matures.

The microscopic wasps, which do not grow stingers, have been the best weapon against the pinhead-size flies, which have been unaffected by pesticides since being discovered in Southern California 19 months ago.

Tom Bellows, a UC Riverside entomologist who is heading the biological eradication research team, said the researchers were “very pleased” with the wasps’ performance.

The Department of Food and Agriculture, in joint effort with the UC Riverside researchers, plans to disperse thousands of additional wasps this spring in a full-scale attack against the flies. The pest, which attacks trees by sucking the juice from leaves, has so far affected apple, peach, pear, plum, apricot, pomegranate, lime and kumquat trees.

But Bellows warned against relying solely on the wasps to wipe out the billions of flies in the Southland. He encouraged the development of additional natural enemies of the flies, such as an imported beetle, which are currently being studied at UC Riverside.

“There’s a lot that we don’t know about the natural enemy of this bug,” he said. “It will take repreated and consistent effort.”