Abstract
The smaller brown planthopper, Laodelphax striatellus FALLÉN, has been reared continuously for over 10 generations on holidic diets. By letting the planthoppers lay their eggs on Parafilm M membrane, the planthoppers were maintained free of their natural host plants for many generations. On holidic diets the nymphal growth was retarded but became improved after the 4th generation, although it was still slower than the controls even at the 10th generation. Nymphal mortality showed similar trends to nymphal growth, increasing up to the 3rd generation and decreasing thereafter. It was also noted that the resulting adults on holidic diets showed apparently no difference in size compared with the controls. In artificial rearing the multiplication rate of the planthoppers were extremely low, probably because of the inadequacy in the collecting methods of their eggs and their preservation. Mortality was found to be very high just after hatching. Therefore, the rearing conditions for the first instar nymphs were examined, and the following became evident. A shorter vessel is better than a taller vessel and as for light source, yellow, orange and red colors are preferable. The higher the relative humidity, the better is the survivorship. The preferred temperature for the first instar nymphs ranges from 15°C to 23°C.
