Codling Moth Caterpillar - a pest of fruit trees. 

Typical Damage to Apple fruit by the Codling Moth Grub - Caterpillar

The Codling moth and its larvae are severe pests to Apples, Plums and Pears. The larvae burrow into the center of the fruit and eat out channels within the fruit which makes them inedible - or for commercial growers - unsalable.

Treatment

It is often written and thought that grease bands applied to the trunk of fruit trees will help to trap or deter the codling moth. Absolute nonsense! No protection from the Codling Moth with grease bands - Codling Moths can fly!

Spray with Bifenthrin two or three times  from  early June - AFTER the flowers have set, or use a Pheromone insect trap. The trap attracts the the males into thinking it is the scent of the female! This will give you an idea of the numbers and timing of the codling Moths in your orchard etc, and you can adjust your spraying programme accordingly.

Killing Codling Moth - or even any degree of control is dependent upon timing, and as such is normally outside the scope of the amateur gardener with perhaps the odd tree or two. However, if you want to be the local 'anorak' at dinner parties, it is an interesting subject - for some.