Abstract
The third to sixth instar larvae of Spodoptera littoralis (BOISDUVAL) (Prodenia litura) were fed on white clover leaves with nuclear polyhedra of Spodoptera for 24 hrs. Then the larvae were reared individually on untreated leaves at 25°C. Larval body weight were surveyed every day.
It was observed that infected larvae tended to die in non-molting form, decreasing their body weight (cf. Fig. II). It was, also, observed that larvae inoculated at the fourth or the fifth larval instar and let fall into the polyhedrosis, probably, at an early half of the sixth or the last instar grew more slowly than healthy larvae did, and some of them reached the body weight of normal full grown larvae at the time of prepupal or pupal stage of healthy insects. (cf. Fig. III &. Table III).
The delay of growth of infected larvae observed at the last instar could be understood from a abnormality that the infected larvae could not increase .and decrease their body weight so rapidly as normal larvae did.
