Lightbrown apple moth		Greenheaded leafrollers		Brownheaded leafrollers
	Leafroller monitoring in organic orchards: Other factors

(1) The bacterial spray Bacillus thuringiensis is frequently used for organic control of leafrollers. Standard pheromone traps can be used for monitoring and determining the need for sprays, as in IFP. However, mating disruption may become another option for leafroller control in organic orchards. This method fills the orchard with high concentrations of pheromone for particular species which prevent the moths from mating. This also prevents male moths from finding pheromone traps so the purpose of monitoring is to confirm that disruption is functioning (i.e. no trap catches).

(2) Pheromone traps catch male moths which emerge ahead of females, mating, egg laying and caterpillar damage. This time lag allows control actions with Bacillus thuringiensis to be taken in the following one to two weeks. If using Bacillus thuringiensis, the time to start trapping is when the crop is first at risk from the first generation of leafrollers. This is petal fall or early November from Nelson northwards but is delayed to late November or early December in the south.

(3) The traps give a good indication of when male emergence begins. To prevent mating by pheromone disruption, dispensers must be placed in the orchard at the start of, or preferably before, male emergence begins. Male emergence begins in late September/early October in the north and early November in the south of New Zealand.

(4) While trapping only for lightbrown apple moth is acceptable in many localities, the greenheaded and brownheaded leafrollers can be locally important in some orchards of Otago, Canterbury, and Hawkes Bay. It is important to trap for these species at these locations and add trap catches together when determining if the spray threshold has been reached.