What's eating my damson?

Damsons share the Prunus pest complex — plum moth, plum sawfly, aphids, and winter moth caterpillars are the main threats, though damsons tend to be more robust than dessert plums. Wasps target the small, tart fruit at harvest. Plum moth maggots are the most frequent cause of premature fruit drop and crop loss.

Larvae tunnel into damsons and feed around the stone; entry holes visible on fallen or harvested fruit. Pheromone traps from late May; spinosad at first adult capture; destroy windfalls promptly.

Fruitlets develop sticky resin at entry holes and drop in late May to June; larvae feed inside before the stone hardens. Pyrethrin or deltamethrin at petal fall targeting the egg-hatch window; remove and dispose of infested drop.

Curled, distorted shoot tips in spring; although damsons tolerate aphid pressure better than dessert plums, heavy attacks weaken new growth. Insecticidal soap or pyrethrin at bud burst before leaf curl develops.

Caterpillars shred blossom clusters and unfurling leaves, reducing crop set especially in exposed sites. Grease bands on trunks and stakes from October; Bacillus thuringiensis at bud burst if heavy infestation.