Insect Pests of Soyabean in Japan and their Control

Abstract

From thirty species of economic importance, the biology, damage caused and control measures for three pod borers, one pod gallmidge and four stink bugs are reviewed. Some high correlations have been recognised between the percentage of injured seed at harvest time and the mean temperatures of January, July or August, and some equations have been obtained for forecasting the percentage of the damage to soyabean seeds. The late podding varieties are generally less damaged by major pests. Even in one variety, damage decreased when sowing was delayed. Hence consideration should be given to the choice of variety and sowing date in order to avoid the coincidence of the peak of pest occurrence with the podding period of the soyabean plants. In the central southern region of the Tohoku district where all species of economic importance occur, insecticidal applications should be carried out when indicated by the forecast, two or three times at intervals of one to two weeks, during early pod-setting and on to the middle seed-thickening stage, using such insecticides as: fenthion, cyanophos, fenitrothion, phenthoate, acephate, chlorpyrifos or EPN.