The role of phenols in the influence of herbal extracts from Salvia officinalis L. and Matricaria chamomilla L. on two-spotted spider mite Tetranychus urticae Koch
The role of phenols in the influence of herbal extracts fromSalvia officinalisL. andMatricaria chamomillaL. on two-spotted spider miteTetranychus urticaeKochExtracts prepared from 2 medicinal herbs (common sageSalvia officinalisL. and German chamomileMatricaria chamomillaL.) were used in this study for biological control of spider mites. Their effect on mortality, fecundity, and development ofTetranychus urticaeKoch on English ivy (Hedera helixL.) was studied under laboratory and greenhouse conditions. The extracts were prepared by soaking freshSalvialeaves or dryMatricariaflowers in ethanol for 24 h, followed by evaporation, and finally suspension of the pellets in water. Full extracts and extracts without phenols were tested. TheSalviaextracts had a higher acaricidal activity thanMatricariaextracts, but the toxicity of both extracts to spider mite eggs was low. The toxic effect of fullSalviaextracts on larval stages and females ofT. urticaewas evident. More than 50% of larvae and females were killed by this treatment in 4 days. Besides, total fecundity of survived females was evidently lower. Mortality and low fecundity after fullSalviaextract application decreased the spider mite population by 76%. The toxicity ofSalviaextracts after removal of phenols strongly declined, so the negative effect of the fullSalviaextract on spider mites was connected with a high concentration of phenolic compounds. The toxic effect ofMatricariaextracts in all tests was much lower and no evident role of phenolic compounds in its extracts was observed.