Study on Action Mode of the Different Parts of Hibiscus trionum L. against Plutella xylostella

The different parts of wild watermelon seedling(Hibiscus trionum L.) were selected to study contacting,anti-feeding and inhibition of growth and development of 3th instar larvae of Plutella xylostella.The results showed that ethanol extract possessed high contacting,anti-feeding and inhibition of growth and development.The contacting activity was seedstemrootleaf;anti-feeding activity was seedstemleafroot;inhibition activity of growth anddevelopment was seedstemleafroot.In the four parts of Hibiscus trionum L.,seed activity was the strongest.When Plutella xylsteua was treated with concentration of 12.50g/L,the corrected mortality rate for 72h was 86.67%,the anti-feeding rate for 48h was 85.94%,and growth inhibition rate for 48h was 79.05%.