Studies on aphicidal efficiency of different stinging nettle extracts

Abstract

Undiluted cold water extract of stinging nettle (Urtica dioica) with an extraction time of 24 h, a fermenting extract of the same plant with an extraction time of 6 days were tested against the aphids of plum (Prunus domestica), red currant (Ribes rubrum) and spiraea (Spiraea vanhuottei) in the field. The efficiency of the preparations was calculated according to the Abbott and Henderson-Tilton formulas. Data were analyzed statistically by one way ANOVA. The cold water extract had no significant effect on theHyalopterus pruni andCryptomyzus ribis populafermenting extract hardly influencedH. pruni but it showed an about 80% — but not significant—efficiency againstAphis spiraephaga.