1. Symptoms Induced by VAA Injection
In 3 hr after the injection of VAA (10, ug/
insect) to the 2nd day last instar larvae, their
segmental muscle became to relax and the
symptom sustained for 1-2 days. When the
pulsation frequency of the dorsal vessel was
counted 1 day after the injection, the frequency
was 49.1+9.6/min (n=18) which was
significantly less than that of the control