Plum moth: how to recognise and treat it

Pest

Plum moth — Photo: Donald Hobern, CC BY 2.0, Wikimedia Commons

Symptoms

A pinkish caterpillar up to 12 mm long with a brown head inside ripe fruit, with brown droppings near the stone.
Drops of gum on the fruit where the young caterpillar bored in, usually near the stalk.
Young infested fruit turns violet and falls early.
Infested fruit colours and ripens earlier than the rest and may be misshapen.

Organic treatment

Spray Bacillus thuringiensis var. kurstaki at the peak of egg hatch, before the caterpillars bore into the fruit.
In September–October, after the caterpillars leave the fruit, spray insect-killing nematodes on the trunk and soil.
Pick up and destroy fruit that colours or drops early.

Chemical treatment

Lambda-cyhalothrin or diflubenzuron at the start of egg laying, timed by pheromone trap catches; follow the label dose and pre-harvest interval.

Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.

Prevention

Hang pheromone traps in early May to catch male moths and time treatment; this works best on isolated trees.
Choose early-ripening varieties, which suffer less than late ones.
Encourage birds, hedgehogs and ground beetles.

Plants it affects

Sources

Figures checked against these sources.