[Insecticidal activity and active components of alcohol extract from Juglans mandshurica Maxim leaves].

The insecticidal active components in Juglans mandshurica Maxim leaves were extracted by conventional method. The alcohol extract and its chloroform-extraction phase showed insecticidal activities in contact toxicity and stomach toxicity against Lymantria dispar L. and Mamestra brassicae L. larvae. When the concentration of the extract was above 10 g x L(-1), the corrected mortality was higher than 50% 5 days after applying the extract. Alcohol extract had higher insecticidal activities than its chloroform-extraction phase. The GC-MS analysis on the active components in the chloroform-extraction phase showed that the main component was juglone (5-hydroxy-1,4-naphthalenedione), and the others were 2,2'-methylenebis-6-(1,1-dimethylethyl)-4-methyl-diphenol and 2-methoxy-4-vinylphenol.