New Pheromone Sprayer Leads Amorous Moths
Astray By Jan
Suszkiw September 27, 2007
For decades, apple and pear growers have "adorned" their orchards with
hundreds of plastic dispensers that emit a chemical sex attractant, or
pheromone, to disrupt codling moth mating. Now, thanks to Agricultural Research
Service (ARS) studies in Wapato, Wash.,
growers could soon be spraying the pheromone instead.
Growers customarily hang the pheromone dispensers from tree limbs by
handoften 200 to 400 of them per acre. It's a laborious, costly affair,
Knight, an entomologist with ARS'
Agricultural Research Laboratory in Wapato.
Although spraying pheromone isn't a new idea, early attempts stumbled
on technological hurdles. In 2003, Knight decided to give it a try based on a
1999 observation he had made while testing a fluorescent dye he had added to a
sprayable, microencapsulated pheromone product developed by a Bend, Ore.,
Using the dye and a black light to examine microcapsule densities on
tree leaves, Knight determined the codling moth pheromone's delivery could be
improved using ultra-low-volume (ULV) spraying. Besides cutting water use from
100 gallons to 1.25 gallons per acre, Knight's approach increased the
microencapsulated pheromone's deposition rate by six- to 10-fold.
His trials in apple and pear orchards since 2003 show that ULV
spraying four to six times a season disrupted codling moth mating as
effectively as the hand-hung dispensers. Knight determined this from
captured-moth counts and reductions in fruit damage. In 2005, he expanded the
studies to include ULV spraying of the insecticide esfenvalerate, which curbed
moth egg-laying by 95 percent.
If unchecked, hatchling moth larvae waste little time boring inside
nearby fruit, ruining its marketability. Besides apples and pears, the pests
also attack walnuts.
Knight is testing reduced-insecticide rates in combination with the
pheromone. And to the sprayer itself, he's making adjustments that include
adding an electronic "eye" to direct pulses of material into the center of a
about the research in the September 2007 issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.