Pink plum maggots – actually the caterpillar larvae of the plum moth – live in and eat the fruit of plums and related damsons and gages, causing “maggoty fruit”.
Adult plum moths are small and have a wingspan of 1-1.5cm (around ½in). The forewings are dark brown with blackish markings and the hind wings are brown.
The adult moths start to emerge from late May, but mainly from mid-June to mid-July. They mate, and the female adult moths lay eggs singly on the underside of the fruit. The eggs hatch into small creamy-white or pinkish, brown-headed caterpillars.
The caterpillars then tunnel into the fruit and feed on the flesh around the stone until late summer. Then, when fully fed, they emerge from the fruit and pupate inside silk cocoons, overwintering in concealed places, including under loose bark. During hot summers, caterpillars can pupate early and produce a second generation of moths in late summer.