Why Are My Apricots Full of Maggots or Grubs?

Discovering that your ripening apricots contain a small white or pink caterpillar and frass when you cut them open is the classic sign of plum fruit moth (Grapholita funebrana). The moth lays its eggs on developing fruits in late spring and early summer, and the hatching larvae burrow directly into the fruit flesh, feeding on the flesh and stone. Affected fruits often drop prematurely — and the caterpillar drops out into the soil below the tree to pupate, completing its lifecycle ready to attack the following year.

Identifying plum fruit moth damage

Affected fruits are often indistinguishable from clean fruit until you cut them open. Some prematurely dropped fruits contain a caterpillar with a small entry hole near the stalk end. Others remain on the tree until near harvest but contain the remains of a larva that has already exited. Cut any dropped fruit before it is discarded — if a larva is inside, destroy the fruit and do not allow it to sit below the tree.

Pheromone traps

Plum fruit moth pheromone traps catch male moths and help monitor the timing and intensity of adult flight. Hang traps in the tree from May. The trap catch indicates when adult moths are active and eggs are being laid — this is the critical window for any protective spraying. High trap catches in some gardens barely correlate with fruit damage levels because female moths have their own preferences, but monitoring helps you understand your local risk.

Control options

Once larvae are inside the fruit, no treatment reaches them — control must prevent egg laying or kill young larvae before they enter. The biological insecticide Spinosad (where approved) applied to the fruitlets when adult moths are active disrupts larvae attempting to enter the fruit. Codling moth traps can double as plum moth traps as both species are caught. Remove and destroy all dropped fruit to break the lifecycle — larvae that reach the soil will pupate and produce the next generation.

Physical barriers

Fine insect-proof mesh (0.8 mm or smaller) draped over small trees or sections of wall-trained trees from May onwards physically prevents egg laying. This is impractical for large trees but highly effective for small or young trees where complete coverage is possible.