This time of year when you eat an apple or pear you may find a maggot, or worse half a maggot in it. This is the caterpillar of the codling moth. I used to think that by placing either a grease band or grease on the trunk of the trees it would stop this but although this might help it is not the best remedy. An organic method is a pheromone trap which is hung in the tree to catch male moths in April and May and will cut down the infestation. Another organic method is a pathogenic nematode (Steinernema carpocapsae) which is available by mail order from some suppliers of biological controls.
Chemically you kill young caterpillars before they enter the fruit by spraying apple and pear trees with bifenthrin in the second or third week of June. Follow this up with a second application about three weeks later.
Grease and grease bands will protect against Winter Moth. These caterpillars are the pest that eat holes in leaves, blossom and young apple fruitlets. Severe attacks can weaken plants. Extensive damage to fruit trees can affect crop yields and quality.
The adult codling moths lay their eggs on or near developing fruit. These eggs hatch into small white caterpillars, which eat their way into the fruit and feed inside whilst it is developing. The caterpillars may be found inside the fruit at harvest time, but have usually eatent their way out to overwinter on the bark of the tree. They will then pupate and hatch into adult moths the following Spring, ready to mate.
The caterpillar’s exit hole is often visible in the side of the ripe fruit or at the ‘eye’ end (opposite to the stalk). When the fruit is cut open, the tunnel and feeding damage inside the core can be seen, together with the caterpillar’s excrement pellets.