Codling moth (apple, pear or walnut fruit worm)

A caterpillar tunnels to the fruit's core: a small entry hole plugged with frass, fruits ripening too early and dropping. It is the most common pest of apples, pears and walnuts.

How to recognise

• Open several affected fruits: look for a brown tunnel reaching the pips and a small pinkish caterpillar.
• Spot a small entry hole ringed with frass (droppings) on the skin: it is the surest sign.

What to do

• Regularly collect and destroy dropped or wormy fruit to break the pest's cycle.
• Set a pheromone trap in spring to track moth flight and time your monitoring.
• Wrap the trunk with a corrugated cardboard band to catch caterpillars coming down to shelter.

Prevent

• A fine-mesh net fitted before egg-laying effectively protects a small tree.
• Encourage tits (nest boxes) and bats, natural predators of the caterpillars and moths.

Trees affected