Allegan , Berrien and Van Buren counties rank second, third and fourth, respectively. MSU Pear Information Definitions of Pear Growth Stages in the MSU Fruit CAT Alert. Only the second generation attacks pears. Pear psylla is a pest which is usually controlled by natural predators on unsprayed trees, but sprays to control codling moth reduce the predators so that psyllas build to levels which injure the tree. Sooty black honeydew on the leaves and fruit are symptoms of this pest.
Pear psylla becomes a major pest when it develops resistance to insecticides.
Grape mealy bug is becoming a pest in some pear production areas. It is normally a minor pest in both grapes and pears but seems to be becoming resistant to common insecticides. Pear leaf blister mite and pear rust mite can cause extensive damage to the fruit. They quickily develop resistance to miticides. Pear slug or pear sawfly is a pest of minimally sprayed trees.