Plum Fruit Moths (Grapholita funebrana) are a dull grey colour and are active from May until September. The eggs are normally laid as individual eggs on developing fruits. These hatch into larvae/caterpillars that enter the fruit to feed. The caterpillars eventually move into bark crevices of the tree in September. Some caterpillars may also move into the plant debris and soil at the base of the tree. There can sometimes be a second generation of Plum Fruit Moths from August to September. This generation tend to pupate the following spring.
The larvae/caterpillars enter fruit, such as Plums and Damsons, and feed inside it. These caterpillars are often known as the Red Plum Maggot, as they are pinkish-white in colour. Black frass is left inside the fruit and the fruit eventually turns into a gooey mess. Infested fruits also tend to ripen prematurely.
The first step in controlling potential infestations is to monitor for Plum Fruit Moth activity. They will often host and feed in Blackthorn, with their larvae feeding on the Sloe fruit. The moths will fly to Plums in late May and be active for most of the summer. To detect their presence put out our Plum Fruit Moth Pheromone Traps by late May. The pheromone lures in the traps will attract and catch some of the male Plum Fruit Moths. This will provide a warning of future damage from their caterpillars and help reduce male moth numbers, which in turn reduces mating.
There is also now a biological control for the Plum Fruit Moth larvae/caterpillars when they are not in the fruit. Plum Fruit Killer Nematodes can be sprayed onto the bark of the Plum Fruit trees, and to the base of the trees, in September and April. This is when the larvae are present on the tree but not in the fruit. Application of nematodes at these times, combined with use of our Plum Fruit Pheromone traps, will drastically reduce Plum Fruit Moth infestations. Find our range of relevant products below.