Abstract
The object of the work described in this paper was to investigate experimentally the overwintering of the brown planthopper eggs and the growth of the larvae hatched from hibernation eggs under the natural temperature condition.
Rearing of eggs were carried out in the weighing bottles containing the small quantity of water, absorbent cotton and filter paper under the natural temperature condition.
The larvae hatched from hibernation eggs were reared in the insectarium using the rice plants cultured in pot.
The results obtained are summarized as follows: 1) According to the results investigated by means of artificial rearing under the natural temperature, it was cleared that brown planthoppers hibernated easily in the egg form and the hibernation eggs hatched from the latter part of April to the early part of May.
2) As the results of successive rearing of the larvae hatched from hibernation eggs, it was cleared that the adults of the first generation emerged in the lastpart of May and the adults of the second generation in July.
3) In Kanagawa district, the first occurrence of the brown planthopper are found generally in the macropterous form (long-winged) at rice fields from the last part of June to July, and from the experiments mentioned above, it was considered that this adults were second generation.
