Adult codling moth (CM) are monitored with traps baited with either CM pheromones or a mixture of pheromones and an attractant (Combo D/A lure). Pheromone traps should be placed in the upper 1/3 of the tree canopy before first apple blossoms open or by 100 DD since January 1 whichever comes first.
Lures and trap color
If you are not using mating disruption, use a 1x (1 mg) pheromone lure; if you are using mating disruption a 10x (10 mg) pheromone lure or a Combo/DA + AA lure is your best choice for monitoring. Each lure will have its own longevity so be sure to replace them at the manufacturer's recommended intervals.
Whichever lure is used, we currently recommend using a red or orange delta trap to minimize capture of honeybees (compared to white traps).
Traps trap should be placed in the top portion of the tree, preferably the top 1/3 of the tree's canopy. Adult moths are most active in those top areas of the tree canopy. Trap placement and checking is easier when the trap is attached with its wire to a pole (bamboo works well, see picture). Foliage should not block the entrance of the trap.
The number of traps used per area is critically important when using moth capture as a tool to determine the need to apply control sprays. Place 1 trap per 2.5 acres to be sure to capture moths at low population levels.
Traps should be checked at least once a week. The number of moths should be counted and removed. Separate records should be kept for each trap capture. Stirring the adhesive surface of the trap after each inspection will increase its effectiveness as moth scales or dust collect on the sticky trap bottoms over time. Change trap bottoms after catching 30 moths, or every time a lure is changed.
If you use the recommended trap density (1 trap for every 2 to 3 acres) then guidelines can be used to assess the need to apply control sprays. In the first generation an accumulation of 4-5 moths in a trap signals the need for a control spray. After a control spray is applied moth captures in each trap should be started over at zero to determine if additional controls are necessary. By examining the distribution of trap captures in an orchard it is possible to treat only those portions of the orchard with high pressure, therefore avoiding treating areas of the orchard where codling moth densities are low. In the second generation it is recommended that an accumulation of only 2-3 moths in a trap be used as a trigger to apply control treatments.
CM population size
The numbers of moths caught can also be used to estimate how big a population is in the orchard by comparing the predicted emergence values given in DAS (e.g. 50% adult emergence) and the number caught in your traps to that point in time.