An Apple for the Entomologist

by Robert Sanders

The U.S. Environmental Protection Agency this month approved the first microbial pesticide against the number one insect pest of apples, a tribute to the single-mindedness of a Berkeley professor and the willingness of organic growers to finance its development.

Louis A. Falcon, professor emeritus of entomology in the College of Natural Resources, embarked on his 14-year quest for EPA registration of the codling moth granulosis virus little realizing the roadblocks he would face.

"Originally I was hoping to get it registered by the time I retired," Falcon said. "Then it was, hopefully I'll have it before I die."

What kept him going was the success of field tests of the microbe, and the enthusiasm of many of the 200 fruit growers--primarily organic farmers and those in transition to organic farming--who tested it.

"Lou has to be given a lot of credit for this. It was something he saw organic farmers really needed, and it was something we had and could work on," said Art Berlowitz, a retired researcher who worked on the project with Falcon.

Funding for EPA tests came from a group of organic growers, the California State Environmental License Plate Fund and the U.S. Department of Agriculture.

The non-profit Association for Sensible Pest Control, Inc., whose membership today includes 14 organic growers from California and Washington, was formed in 1988 with the specific goal of supporting Falcon's work on the virus. At the time there were no other alternatives for organic growers.

"We've been waiting for this for years," said Tim Bates, who grows organic apples and pears in Philo, Calif., under the name "The Apple Farm." Bates, who also is on the association's board, has used the virus under an experimental use permit for the last eight years.

The codling moth is the principle pest of apples and pears throughout the world. It is well known for its little pink worms or larvae that used to be a common sight after that first bite of an apple. The codling moth granulosis virus is a naturally occurring baculovirus that makes the worms lethargic and eventually dissolves them from the inside out. Baculoviruses infect only arthropods, that is, insects and related species.

Field tests by Falcon and Berlowitz in the early 1980s showed that with proper application, the baculovirus could control the worms as effectively as chemical pesticides, including the most commonly used pesticide azinphosmethyl, marketed as Guthion. And because the baculovirus attacks only a narrow range of closely related species, leaving other insects and spiders alone, application did not encourage the proliferation of secondary pests such as mites, scale insects and aphids.

Broad-spectrum pesticides like azinphosmethyl usually kill all insects in a field, the good and the bad, Falcon says.

Falcon doesn't claim the baculovirus will supplant chemical pesticides, since it is more labor.

"A program could be put together, using baculovirus and pheromones, that could practically eliminate chemicals on apples and pears, especially on the West Coast," Berlowitz said.

For the moment it's unclear who will produce the baculovirus, which is registered to the University of California and ASPCI for use on apple, pear, walnut and plum trees.

The codling moth granulosis baculovirus was first discovered in sick Mexican worms in 1963 by Leopoldo E. Caltagirone and identified by Yoshinori Tanada, both now professors emeritus of entomology at Berkeley. Falcon produced enough of the baculovirus to start field tests, and in 1981 began to seek EPA approval.

He initially sought the assistance of chemical companies, but they lost interest after concluding that only organic farmers would be interested.

Rather than drop the project, Falcon decided to seek registration himself through UC. In doing so he was entering a field alien to most academics, who typically hand off their research findings to industry to develop and market.

"This marks the first time a UC campus has ever taken the steps to register such a product," Berlowitz said.

"The baculovirus affects very, very few species of insects--fewer than you can count on the fingers of two hands," Falcon said. "This product is extremely safe, non-pathologic, and is accepted by the organic fruit industry as a natural pesticide."

While one of only a few available choices for organic farmers, the baculovirus should also be of interest to those who now use chemical pesticides and want to reduce dependence on them. In fact it comes at a time when farmers are finding codling moths resistant to Guthion, Falcon says. Integrating use of the baculovirus with judicious application of chemical pesticides could keep the moth at very low levels in the orchard.

"The major lesson I've learned is that you can't rely on just one thing to control pests," Berlowitz emphasizes. "You must have a multifaceted approach, where chemicals play a role too."


Copyright 1995, The Regents of the University of California.
Produced and maintained by the Office of Public Affairs at UC Berkeley.
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