Biological effects of Sambucus ebulus L., Urtica dioica L., Rubus fructicosus Boiss. and Pteridium aquilinum (L.) Kuhn) extracts against two-spotted spider mite

The study of the plant compounds efficacy for pest control is one of the expanding researches in most agricultural systems. In this research, the efficacy of aqueous and ethanolic extracts of four plants including dwarf elder (Sambucus ebulus L.), common nettle (Urtica dioica L.), blackberry (Rubus fructicosus Boiss.) and eagle fern (Pteridium aquilinum (L.) Kuhn) was assessed against the adult female of Tetranychus urticae, one of the most important pests of crops and greenhouse plants. The acaricidal effect of the extracts and their long-lasting effectiveness were studied as well as their oviposition deterrent effect. Two experiments included the long-lasting effectiveness (with the concentrations of 0.5, 1 and 1.5 mg/cm2) and oviposition deterrent effect (with the concentrations of 0.4, 0.7 and 1 mg/cm2). The study of extracts was conducted in a completely randomized design. The aqueous extract of blackberry did not have any acaricidal effect on the pest, and this effect varied from 9.2 to 49.8 % for other aqueous extracts. The LC50 values for ethanolic extracts of dwarf elder, common nettle, blackberry, and eagle fern against the adult females of the pest were obtained to be 0.54, 0.82, 0.76 and 0.72 mg/cm2, respectively. The study of long-lasting acaricide effectiveness of the ethanolic extracts showed that the common nettle extract had high long-lasting effectiveness of 48 hours, after which the extracts of blackberry, dwarf elder, and eagle fern were respectively placed. The blackberry ethanolic extract had the highest oviposition inhibitory effect in comparison with other extracts (94% at 1 mg/cm2). The results demonstrated the appropriate efficacy of the ethanolic extracts to control T. urticae pest in comparison with the aqueous ones, and accordingly, evaluating their control capacity under field conditions will provide some practical valuable data. Amongst the ethanolic extracts, dwarf elder displayed the most acaricidal effect.