The codling moth (Cydia pomonella) is a regular pest of apple and pear orchards where it causes considerable economic losses. Damage to fruit is caused by the larva (caterpillar) of the moth.
Damaged fruit is recognizable by the brown-rimmed holes in the skin. Underneath these holes, the caterpillar has tunneled its way to the core and feeds on the protein-rich seeds. This tunnel may contain the brown, granulated excrement of the caterpillar, also called frass. Damaged fruit ripens earlier than healthy fruit and falls prematurely, which causes yield loss.
Adult moths are greyish with light grey and copper stripes on its wings. They occur from late spring until late summer and even early autumn if night temperature remains above 15°C. After 3 to 6 days from emergence, female adults lay eggs on leaves and fruits. After 1 to 3 weeks, depending on climatic conditions, black-headed yellow larvae start to penetrate fruits immediately after hatching. One larva can damage several fruits. By the end of summer, after tunneling inside the fruit for about 3 weeks, caterpillars leave the fruit to hibernate in fissures on the trunk and branches, rocks and fence posts. Next spring the larvae pupate and a new generation will be ready.