Damage. The caterpillar of this species tunnels into the branches and trunk of a wide range of tree species, such as apple, ash, birch, and lilac. The tunnelling may weaken the branches of trees which in high winds commonly break.
Life cycle. The Leopard moth has an unusual life cycle. The moth is large, 5-6 cm across, and is white with black spots. In early summer the female lays dark-yellow eggs on the bark of the tree. The emerging caterpillar (see Figure 14.14) enters the stem by a bud, and then
tunnels for 2-3 years in the heartwood. It has bacteria in its gut which help to digest the xylem tissue that it eats. It eventually reaches 5 cm in length, pupating in the tunnel, and finally emerging from the branch the following summer as the adult. Spread is only by adults.
Control. Where tunnels are observed, a piece of wire may be pushed along the tunnel to kill the larva.
Other moths worthy of mention here are the fruit-invading species such as codling moth (Cydia pomonella) on apple, plum moth (Cydia funebrana) and pea moth (Cydia nigricana) each of which needs accurately timed insecticidal control to avoid fruit damage by the pest (see also pheremone traps), because insecticidal control inside the fruit is not possible.
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