Pheromone traps
The flight activity of male moths should be monitored using sex pheromone traps. 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 4-6 weeks as recommended by the manufacturer.
- It is important to change them before the second generation.
- Sticky bases should be changed if their effectiveness declines.
- The threshold for determining whether the pest is a problem in an orchard is 30 moths per trap per week.
- However, temperature sums to predict egg hatch to determine correct timing of egg hatch sprays should be started from the date when the catch exceeds 5 moths per trap (see ‘Forecasting’ ).
Shoot damage
- During the first half of July, leaves tied by spinning larvae are easily recognisable on the top of the shoots.
- If shoot damage exceeds 5-8%, a curative treatment should be applied immediately or postponed to the beginning of egg-hatch of the second generation.
Fruit damage
- Inspecting 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), indicates if populations have been high and whether treatment is likely to be required for the next generation or the next season.
Trunk banding
- Trunk bands can be set on a sample number of trees in early September and the number of overwintering larvae counted during the dormant period.