Editors:

To schedule an appointment to observe puffer can preparation at Dr. Shorey's UC Kearney Ag Center laboratory and/or installation of the cans in their new cabinets in the field, call Jeannette Warnert at (209) 225-5611.

Aerosol cans strategically placed at 10,000 sites on the Valley's west side and in coastal areas near Oxnard will soon be methodically puffing a scent into the air that could confuse a devastating pest practically out of existence and usher in a new genre of agricultural pest control.

Using technology borrowed from public restroom deodorant dispensers, University of California entomologist Harry Shorey is beginning large-scale demonstrations this spring of a system he designed to charge the air so full of a female insect's sex attractant pheromone it nearly eliminates the possibility of a male ever finding one to mate.

If the experiments prove successful, growers will have a new environmentally benign, automated and inexpensive pest control system on their side in the continuing battle to control agricultural pests.

Using pheromones in agricultural pest control is not new. However, distribution methods have been imperfect. The puffer may be the element that makes mating disruption effective and practical in a wide variety of cropping systems.

The puffer:

• Releases pheromones at a constant level throughout the season. Other systems resulted in a tapering off of pheromone release as the dispenser ages.
• Protects pheromones from chemical breakdown in the field because it stores it in an oxygen-free environment.
• Can be programmed to release pheromones at certain times of day, so periods when insects are most active can be targeted.
• Can dispense "cocktails" of pheromones to control several pests at once.

Pheromone confusion breaks the weak link in pests' natural life cycle. Male and female moths, Shorey said, do not congregate together. When a female is ready to mate, she releases an odor. A male catches the scent and instinctively zigs and zags in flight upwind following the trail.

"The idea behind mating disruption is jamming that signal," Shorey said.

A single puff from the can releases the pheromone equivalent of five to 10 million moths. The puff becomes a mile-wide swath that can travel as much as 10 miles downwind.

"I liken it to an enclosed cooking competition where all the contestants are using garlic," Shorey said. "Upon entering, you might be overwhelmed by the scent. But after constant exposure, you don't smell it anymore."

Previous research has suggested that the 1998 project will be effective. Shorey placed one puffer with beet armyworm pheromone per acre in a 160-acre block of tomatoes. In another study, one puffer for each 50 acres dispensed the pheromone in a nine-square-mile area.

"In both cases we got about 75% control of beet armyworm moth egg laying," Shorey said. "The smaller block probably had an adequate concentration of pheromone, but was not big enough to prevent some female moths that mated outside the area from flying in and laying eggs. The nine-square-mile block may have been big enough to prevent the problem with fly-in females, but the pheromone concentration may have been too dilute to totally prevent mating in the block."

Using this information and other research results, Shorey arrived at this year's strategy. Puffers will be placed around the perimeter of 40-acre blocks in large, contiguous agricultural production areas, at an average of one puffer for each four acres.

"We feel this should provide effective control of beet armyworm breeding and egg-laying," he said.

While extremely promising, Shorey's research has been fraught with technical difficulty, primarily caused by the use of indoor air freshener dispensers outdoors. For 1998, puffers take a technological leap. New cabinets specifically designed for the experiment have no moving parts, can be hung in trees or attached to stakes in the ground, and are equipped with computer chips that automatically turn the unit off when temperatures drop to levels in which pests are not active. Adjustments may be made by remote control, not unlike those used for televisions.

"The technology is moving so fast," Shorey said. "The next generation may be radio controlled. Ultimately, a console at a remote location will control all puffers in the field, where they are able to take into account not only temperature, but also wind direction and other factors."

While the research is now at a critical juncture and the system could be commercially available as soon as next year, there are years of research ahead on puffer use for pheromone confusion.

"There are still many unanswered questions about this system," Shorey said.

Jeannette Warnert
Public Information Representative
UC Regional Office
550 E. Shaw Avenue
Fresno, CA 93710