Pesticides in Grain Hamper Medfly War : Agriculture: The chemicals killed larvae needed to produce sterile Medflies, which are in short supply. Wanted: organic wheat.

Mediterranean fruit fly fighters in California are scrambling to find a good source of organic wheat after pesticide-tainted grain killed larvae and stopped production of sterile Medflies at laboratories in Hawaii for two weeks.

The sterile flies are released into infested areas in an effort to eradicate the Medfly population, which is considered a major threat to California agriculture. There is already a shortage of the sterile flies, which the tainted-grain incident has worsened.

The pesticide contamination “meant that we were not able to have the distribution level we would like to have had,” said Fred Meyer, deputy project director of the state/federal Medfly Project. “We feel it did not jeopardize the program because we were able to get some (sterile flies) from Mexico.”

But it was another setback for the troubled effort to rear enough sterile Medflies to get rid of the current Southern California infestation.

Fly fighters would like to release 800,000 sterile flies per square mile every week in the affected area of 343 square miles. During the last week in May and the first week in June, Meyer said, only 530,000 per square mile were released.

Now that it has learned the danger of pesticide to the program, the government is looking for enough organic wheat to feed hundreds of thousands of larvae each week. The irony is not lost on organic farmers.

“That sounds just like the California Department of Food and Agriculture, doesn’t it?” said Allen Garcia, owner of Garcia Family Farms in Orland, Calif., and an organic farmer. “They try to grow sterile Medflies on polluted wheat and grind the whole program to a halt. That ought to teach those boys something.”

The pesticide problem cropped up first at the U.S. Department of Agriculture’s Hawaii Sterile Fruit Fly Rearing Facility in Waimanalo on Oahu, said Glenn Hinsdale, director of the facility. The lab, which opened in January, is the newest Medfly nursery and is grappling with a host of other troubles--so many that it was impossible at first to pinpoint the cause of the larvae kill.

It was early May, Hinsdale said, when the facility reached its initial goal of rearing 100 million sterile flies a week. But the success only lasted four or five days.

“Being a new facility, there were several problems you could have: microbes, diet, environmental-control problems which we know we have,” Hinsdale said.

At the end of May, production fell to 11 million larvae per week. And between May 31 and June 4, “it dropped out totally,” Hinsdale said.

“We all are experiencing complete bust,” said Nori Tanaka, technical director of the California/Hawaii Medfly Laboratory in Honolulu, which runs two rearing facilities. “Our production went down to nothing for that week.”

Hinsdale didn’t know about the problems at Tanaka’s lab until June 4, when he contacted it, he said. That call enabled the researchers to narrow the problem to the diet of the larvae--the only thing the three facilities had in common.

The larvae were being fed wheat shorts, a high-bran byproduct of the milling of white flour. All three insectaries used the same supply of wheat shorts. Tests showed that the culprit was a pesticide called methyl chlorpyrifos, sold under the trade name Reldan, among others, Hinsdale said, and used to combat the Russian wheat aphid.

Although it took a month to pinpoint the problem, the insectaries had earlier begun testing alternate diets and found that the larvae flourished when fed pesticide-free grain. So they called Sacramento and tried to order some.

Meyer said it took three weeks for the Medfly Project to find feed that had pesticide levels low enough not to kill the Medfly larvae. The agency bought 12,000 pounds and shipped it to Hawaii, where it arrived Sunday.

The hunt is still on for truly organic wheat shorts, so that all future larvae can be reared safely, Meyer said. But the Medfly Project may be searching for a long time.

“When you’re talking wheat shorts, you’re talking a very, very small amount of what comes off the grain in the milling process, just a couple of percent,” said Bob Moore, owner of Moore’s Flour Mill in Redding, Calif. “In order to produce enough of the material they need, you have to produce a huge amount of organic white flour--which there’s a very limited market for.”

The problem is that most people who want organic flour want a whole-grain flour, in which nothing is removed in the milling process, said Moore, who has contacted the Medfly Project and is working on finding an organic alternative feed.

“Nobody’s going to be interested in paying a higher price for organic white flour,” he said. “If they want pure organic shorts, I don’t know how they’re going to do it. It’s certainly nothing I could do.”