Effect of Injury by Adult Megacopta punctatissima (Montandon) (Hemiptera

The effect of injury by adult Megacopta punctatissima on the growth of soybean during the vegetative stage was examined by releasing adults among potted soybean plants. The growth of the main stem was suppressed at a higher density of release. The numbers of nodes and trifoliolates on the main stem also decreased at a higher density of release. The earlier the stage of soybean growth at the time of release, the lower the values of growth indices of the soybean, such as the length or number of leaves on the main stem. The growth indices of soybean, such as the stem length, the number of nodes on the main stem or trifoliolates decreased during a longer release period. Flowering became later, as the start of release became earlier, or the release period became longer. Under the condition showing the greatest influence, that is, release of adults over 30 days starting during stage V3, the length of the main stem decreased significantly at a density of 40 or more adults.