Plum Moth

When it strikes

When and where to look

Scout the planting while temperatures hold between 15°C and 30°C.

Rule these out first

Same category, and at least one host crop in common — so they are genuinely confusable in the same part of the garden.

• Aphids

The signs that lead here

• Fruit rotting or spoiling

Full problem lists for these crops

• 🍑 Plums

About

Plum fruit moth (Grapholita funebrana) is the plum equivalent of codling moth. The caterpillar bores to the stone and feeds around it, and an infested plum ripens and drops early — which is why the crop seems to fall in June and taste fine, until you cut one open.

Symptoms

Premature ripening and fruit drop from July. A small hole near the stalk with brown crumbly frass around it, and a pinkish-white caterpillar in a tunnel beside the stone when the fruit is cut.

Organic Treatment

Hang pheromone traps from mid-May — in a garden with one or two trees the traps catch enough males to reduce damage measurably, not just monitor it. Collect and destroy fallen fruit twice a week, and put grease bands and corrugated cardboard traps on the trunk to catch larvae descending to pupate.

Chemical Treatment

A pyrethroid timed 7–10 days after the first sustained trap catch targets newly hatched larvae before they enter the fruit. Once the caterpillar is inside, nothing reaches it.

Prevention

Use traps every year rather than reacting to damage, keep the ground under the tree clear of fallen fruit, and encourage tits and other insectivorous birds with winter feeding and nest boxes.