What is pear midge?
Pear midge is a pest that can destroy developing pear fruitlets. It is caused by the gall midge Contarinia pyrivora. Tiny flies hatch from cocoons in the soil in early spring, and they can often be seen in swarms around the pear tree in the couple of hours before sunset. They mate and lay eggs in pear blossom before it opens. These hatch and the larvae feed inside the developing fruitlets, which blacken starting from the eye and drop off the tree in late May-early June. The larvae emerge from the fruitlets, enter the soil, spin a cocoon at a depth of about 5 cm underground, and pupate in the spring.
How to deal with pear midge
Keep an eye on your trees and remove any infested fruitlets before they fall, so ideally by mid-May. Unfortunately the initial symptoms are hard to spot: affected fruitlets are slightly larger and softer than normal, because the maggots hollow them out. Blackening at the eye end will become visible by the end of April. For confirmation, cut open a fruitlet and you will see the white maggots inside. Destroy all the fruitlets that you collect.
Other methods of control are to lightly cultivate the soil below the pear tree from June on, to a depth of about 10 cm, using a fork or trowel, so that winter weather and birds will destroy some of the cocoons. If you have chickens, consider constructing a run around your fruit trees, because chickens are very effective at eliminating the maggots from the fallen fruitlets.