Insect Breeders Say Widespread Spraying May Threaten Firms

Widespread aerial spraying of the chemical malathion could devastate Ventura County’s insectary industry, which prospers by selling farmers harmless bugs that eat other crop-threatening pests, company managers said Tuesday.

But those who make their living fighting insects with insects say limited ground-level spraying, or localized aerial spraying, of malathion to kill Mediterranean fruit flies poses no immediate threat to their businesses.

Managers of local insect-breeding farms said they support the latest attack plans against the county’s Medfly infestation. So far, agricultural officials have limited the Medfly war to spraying malathion within a 4.5-mile radius of where 43 Medflies were found near Camarillo.

“At this point the emphasis should be on eradication,” said John Freeman, manager of Sespe Creek Insectary, a Fillmore-based company that breeds parasitic wasps for sale to area citrus growers.

“It’s a small infestation and control measures should be taken,” Freeman said. “Everybody’s got to play it by ear.”

Many Ventura County farmers rely on natural beneficial insects such as wasps or beetles to eat other insects that threaten the area’s thousands of acres of lemon, orange and avocado groves.

But any extended exposure to malathion, the pesticide approved to help control the Medfly, could jeopardize the biological pest-control industry because it would kill the beneficial bugs as well as the bad ones.

Integrated pest-management programs use a variety of insects and small amounts of pesticides to control crop-eating predators. The effort dates back to the 1920s, when farmers concerned about exposing their fruit to unhealthy chemicals first introduced the beneficial bugs.

Insectary managers said they have not discovered any insect that would prey on Medflies and effectively control them. And without such a biological solution, the managers agree there is little alternative to malathion.

“Spraying is going to have some effect on the (biological) program, but it’s not going to stop it,” said Libby Ouellette, a supervisor at the Oxnard Pest Control Assn., a cooperative insectary of about 60 growers.

“We’ll just have to pay attention to when they’re spraying and maybe not release that day” in that area, said Ouellette, who breeds a type of beetle that eats mealybugs.

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But Ouellette and several other managers of Ventura County’s seven insectaries are concerned that if the limited aerial or ground spraying does not work, more serious steps might be taken to kill the Medflies.

In Corona, a Riverside County city that experienced a similar Medfly infestation a year ago, business dropped 10% or more at an insectary where aerial spraying was done for nine months, an insectary manager there said.

“We weren’t able to release our (insects) because the spray killed them,” said Joe Barcinas, general manager of Foothill Agricultural Research, a Corona-based company that sells parasitic wasps and other predators to hundreds of California farmers.

“We had to wait until the residue was gone,” he said. “It also affected us because in some orchards we sustained a lot of pest problems because of the malathion.”

The county’s agricultural community has prided itself in using biological controls and using pesticides only as a last resort, said Phil Phillips, a farm adviser with the University of California cooperative extension in Ventura. “But when it comes to an exotic pest like the Mediterranean fruit fly,” he said, “we have to reassess or re-prioritize.”

According to the protocol set up by the Cooperative Medfly Project in conjunction with state and federal agricultural officials, the prescribed amount of malathion is 2.8 ounces mixed with nine ounces of corn syrup per acre.

“Malathion is a non-selective pesticide, so it will kill the beneficial insects it contacts as well as the target species,” Phillips said. “If there is a plus here at all for malathion, it’s that we’re using small amounts.”

County Agriculture Commissioner Earl MacPhail said the small amounts of malathion to be used in ground spraying would probably not have any adverse impact on local insectaries.

“As little malathion we’ll be using per acre, I don’t feel that the (biological pest-control) program will be affected,” he said.

Times staff writer Joanna M. Miller contributed to this report.