STUDIES ON THE BIOACTIVITY OF RHODOJAPONIN-III TO THE LARVAE OF SPODOPTERA LITURA AND PLUTELLA XYLOSTELLA

Bioassays of rhodojaponin-Ⅲ,for insecticidal effects on the larvae of Spodoptera litura and Plutella xylostella were carried out.The results showed that AFC 50 of rhodojaponin-Ⅲ against the 5th instar larvae of S.litura were 16.93 μg·ml -1,19.31 μg·ml -1 and 16.96 μg·ml -1 24 h,48 h and 72 h after treatment,respectively.Treatment with 100 μg·ml -1,the development perviod of larvae of S.litura were 22.36 d,the mortality was 39.72%,the pupating rate was 33.95%,the weight of the female pupa was 0.296 g/pupa.At concentration of 500 μg·ml -1 of rhodojaponin-Ⅲ,the mortality was 53.33% 4 days after treatment and the pupating rate was only 16.67% against 3-rd instar larvae of Plutella xylostella.