Abstract
In an attempt to breed the rice stem borer during successive generations on synthetic diets, it was found recently that the borer requires ascorbic acid in its food. By addition of this acid into the food medium, the borer can be reared generation to generation.
Two to four hundred milligrams of ascorbic acid per 100g diet seem to be suitable for normal growth of borer. On the diet containing ascorbic acid at such level, weight of larvae, percentage pupation, percentage emergence of normal female moth, number of egg masses laid, and hatchability are all increased. Larvae at the late stages of development require much amount of ascorbic acid as compared with young larvae.
The dry yeast, which is an essential composition of synthetic diet, could not be replaced by known nine B-vitamins. This suggests that the borer requires unknown dietary factors present in the dry yeast, rice bran or rice stem, in addition to the known vitamins.
