Lightbrown apple moth		Greenheaded leafroller		Brownheaded leafroller

Leafroller females produces a potent mixture of pheromone chemicals which attract males for mating. Mating disruption exploits this behaviour by inundating the orchard with high concentrations of the pheromone. When this is done, few or no males are able to find females within the pheromone cloud and mating is prevented. Each leafroller species produces a unique blend of chemicals which make up its pheromone. Lightbrown apple moth disruption requires its own specific pheromone mixture. However, the greenheaded and brownheaded leafrollers' pheromones have some chemicals in common and a single mixture is being tested for disruption of the whole complex of species. Mating disruption has been developed for commercial use against codling moth and it is highly effective, but mating disruption of leafroller has so far been confined to resistance management. Leafroller disruption has been tested using the Shin-Etsu capillary dispenser, which contains pheromone within a capillary tube and slowly releases it over the season. Leafrollers have two or more generations per year and control trials have used two applications of 1000 dispensers/ha, one applied in spring and the other in mid summer.

The dispensers should be placed as high as possible in the trees but below foliage, sheltered from the sun. Extra dispensers are advisable in place of missing trees or around gaps in the foliage canopy. The canopy is important in keeping the pheromone cloud in the orchard. Mating disruption is most effective on large areas (minimum 3 ha). This minimises edge effects where the pheromone cloud breaks down, and where mated females may fly into the orchard from outside. Wind breaks up the pheromone cloud and shelter belts can be valuable in reducing this problem.

The effectiveness of disruption can be monitored with pheromone traps (i.e. no moths should be trapped).