Insecticidal activities of novel pyrazole amides containing hydrazone substructures against Plutella xylostella

Thirteen novel pyrazole amides containing hydrazine moiety were detected for their contact,stomach and anti-feeding activity in laboratory against the 3rd instar larvae of Plutella xylostella ,by using insect-dipping method,leaf sandwich method and leaf disc method respectively.The results showed that these compounds possessed high stomach activity and anti-feeding activity against the larvae.Among these compounds, H7 ,which contains chlorine atoms in benzene ring and heteroatom in the acylhydrazone moiety,had the strongest contact and stomach activity which is much higher than that of control agent chlorpyrifos.The results indicated that the LC50 value of 72 h stomach toxicity of H7 and chlorpyrifos against P. xylostella were 0.6 and 7.4 mg/L,respectively.Additionally,there were 10 compounds that showed higher anti-feeding activity than that of chlorpyrifos against P. xylostella ,and the 48 h AFC50 (concentration causing 50% antifeedant rate) value of H7 was 0.6 mg/L, while that of chlorpyrifos was 6.5 mg/L.All tested compounds showed no contact activity against P.xylostella.