Pest Management Options: Mating Disruption
Female moths emit a chemical blend (pheromone) that forms a plume. Male moths follow the plume to find their mates (top). In the presence of mating disruption, the female moth’s plume is mixed with the plumes of pheromone dispensers, which inhibits the male’s ability to find the female (bottom). The male may either fly randomly and not approach a moth at all (thin dotted line) or home in on a dispenser or even a female (thick dotted line). The idea is that mating is either delayed or prevented.
Examples of mating disruption dispensers, including an aerosol release device, a loop device, and a clip device.
Mating disruption (MD) is an alternative pest control option for codling moth, peach twig borer, and greater peachtree borer. Although MD is certified organic, many conventional growers utilize this technology to increase profitability. The cost of an established mating disruption program is the same or less than a spray program.
Under normal circumstances, male moths find female moths for mating due to the species-specific scent (called a pheromone), that females exude. Under MD, an orchard is saturated with that same female pheromone, “confusing” males and preventing them from finding females. Mating never occurs or is significantly delayed. After several seasons of MD use, the target pest population declines and insecticide sprays may be unnecessary. MD works best in large areas, and expanding MD to cooperating, neighboring orchards will improve effectiveness.
When starting a new MD program, it is important to first know the initial pest population level. Use monitoring traps for at least one previous season to determine general pest levels, outside pest pressure, and hot spots. The first two years of MD will almost always require a full spray program at the same time, to bring pest population levels down.
Mating disrupters are called “dispensers”. Most dispensers target just one pest, and are applied by hand either by twisting, looping, clipping onto a branch, or attaching to a post. (Sprayable MD, though available, has not proven effective.)
- hang hand-applied dispensers singly, and evenly, in the orchard canopy (do not bunch many in fewer locations)
- choose sturdy branches for hanging so that dispensers remain attached even in high winds
- reapply a fresh batch of dispensers each spring (for one season of control)
- store leftover dispensers in the freezer for up to one year to use the following spring
- for new mating disruption orchards, double the application rate on the borders and at “hot spots”
- as moth populations decline, there is the option of lowering the application rate (not on the borders) to save costs
- monitoring the target pest using pheromone traps is essential to determine pest pressure and need for supplemental sprays
Causes of Failure
- using MD in a small area (less than 10 acres for codling moth or peach twig borer)
- not increasing MD dispenser rates in "hot spots" such as along borders or areas upwind of strong prevailing winds
- applying MD dispensers after biofix (first moth flight)
- not applying MD dispensers according to labeled recommendations
- not applying supplemental insecticides when necessary
- not monitoring for sudden increases in moth populations and/or fruit injury
- not maintaining sanitation practices (e.g., removing cull piles and bins)
- using MD in newly planted orchards, which are not ideal for mating disruption because the pheromone quickly dissipates due to lack of foliage