Economic threshold of injuriousness of the most important pests of cereal crops.
The economic threshold of injuriousness of a given pest is a measure of the degree of abundance or infestation that causes an economic reduction of yield, and it has become the basis for the recommendation of control measures. In the USSR, a loss of 3-5% of the cereal crop is considered normal, and the threshold of injuriousness of any pest is the value that will increase the loss beyond that level; the factors involved in this figure are discussed. The problem of the economic threshold is discussed with reference to the grey grain moth [Apamea anceps (Denis & Schiff.)], especially on wheat, the noxious pentatomid [Eurygaster integriceps Put.], also on wheat, cereal aphids (without mention of species), and thrips, of which several are mentioned by their Russian common names and of which the most important appears to be the wheat thrips [Frankliniella tritici (Fitch)] in which the threshold differs for the adults and the larvae.