SURVEYS OF CEREAL DISEASES AND PESTS IN THE NETHERLANDS .6. OCCURRENCE OF INSECT PESTS IN WINTER-WHEAT

Between 1980 and 1986, commercial winter wheat fields at the milky-rip e stage were surveyed for insect pests. Leaf injuring insects were com mon. On average 42% and 95% of the surveyed fields were injured by lea f miners and the cereal leaf beetle, respectively. On average 14% of t he leaves was skeletonised by the cereal leaf beetle and leaf injury t ended to be high in seasons after winters with low temperatures. Bloss om midges were the most important midges. In the period 1980-1984, the orange and lemon blossom midge infested 71 and 21% of the surveyed fi elds, respectively. Insecticides were mainly used to control aphids. D espite control, on average 80% of the fields and 22% of the tillers we re infested by aphids.