Bioactivities of Five Plant Extracts on of Plutella xylostella(L.)

The insecticidal activities of five types of extracts from four plant species against the 2nd instar larvae of Plutella xylostella(L.) were tested in the current investigation.The results showed that the extracts of S.sebiferum had strong bioactivities.The antifeeding rate of the extract from its leaf was up to 69.14% in 24 h and 86.15% in 48 h,while that of the extract from its R.communis branch reached to 56.08%in 24 h and 82.00% in 48 h.All of the three extracts,which were extracted from the seeds of S.sebiferum,the whole plant of R.communis or the leaves of P.serrulata,demonstrated a strong poison effect.Tested with these extracts,the corrected mortality of the 2nd instar larvae of Plutella xylostella(L.) were 82.68%,81.10% and 80.32%,respectively,after 6 d.