Abstract
Mulberry sucker, Anomoneura mori SCHWARZ (Hemiptera-Homoptera: Psyllidae), is one of the serious pests of the mulberry tree, distributed throughout Japan. This insect has only one generation per year, and overwintering takes place in the adult-stage. The resurgent adults assemble on the young tender shoots of the mulberry tree as early as the latter part of May in Hokkaido, and the female deposits its eggs on the under surface of young leaf blades. The incubation-period is about 18 days. The nymph takes about 22 days for its growth. During its growth the nymph has invariably four moults making five instars. By advancing instars antennal segments increase their numbers, viz. I: 3, II: 3, III: 4, IV: 8, and V: 10. One of the remarkable habits of this nymph is the secretion of a white thread-like waxy substance. When the eggs and the young nymph suckers are supplied with mulberry leaves by an oversight, the silkworms do not dislike to eat them. In such cases, however, delay of pupation and decreases of weight and size of the cocoon as well as the reduction of resistance against diseases are recognizable. The moths from such silkworms have a tendency to show shortened longevity. These phenomena may not be due to harmful food disagreement by feeding on eggs or nymphs of sucker, but may be attributed to the indirect influence of the disability of alimentation as a result of eating the wrong food.
