Pheromone traps
The flight activity of male moths (along with that of the codling moth, summer fruit tortrix moth and fruit tree tortrix) should be monitored using sex pheromone traps (a different trap is used for each species). The delta design is used widely.
- Traps should be set out in orchards shortly after blossom.
- Each orchard should be individually monitored with a trap. The traps should be hung from the branch of a tree at mid canopy height in the centre of the orchard and oriented to allow flow through of the prevailing wind.
- The number of moths should be recorded weekly, and captured moths removed.
- Lures should be changed every 6 weeks as recommended by the manufacturer. Sticky bases should be changed if their effectiveness declines.
- The economic threshold is considered to be 30 moths per trap per week, though this may be a conservative estimate.
- Temperature sums to predict egg hatch to determine correct timing of egg hatch sprays should be started from the date when the first threshold catch is recorded.
Caterpillar damage
- Inspect leaves for evidence of leaf roller activity in May-June.
Fruit damage
- Inspect fruits for damage, either whilst developing on the tree, at harvest or during grading (remembering that badly damaged fruit may have been discarded at harvest)’
- This indicates if populations have been high and whether treatment is likely to be required for the next generation or the next season.