Agriculture Reference
In-Depth Information
Figure 6.1
Walnut BIFS grower Chris Locke explains to a neighbor how an aerosol
pheromone dispenser disrupts the mating of codling moths in his orchard.
makes mating disruption easier. Walnut trees are two or three times this
height, and have the greatest volume of any orchard crop in the state.
Scientists developed wax emulsions to squirt high into the canopies of
walnut trees, but they are most enthusiastic about developing microen-
capsulated pheromones that growers can spray with a conventional
spray rig.
Early failures in preventing mating were determined to be from mated
females invading from neighboring orchards, giving added weight to
cooperative pest-control efforts. With additional research, scientists real-
ized they were not fully preventing mating, but reducing it and delaying
a significant portion of it. When the second-generation eggs hatch over
an extended period of time, the resulting adults find fewer mates because
they are spread out over time, which can result in a general decline in
population numbers. Orchards with high populations of codling moth
cannot be managed with mating-disruption technologies alone. The tran-
sition to successful mating disruption requires a conventional insecticide
