Toxic Effect of Four Different Plant Extracts on Potato Tuber Moth [(Phthorimaea operculella(Zeller) (Lepidoptera: Gelechiidae)] Eggs and Larvae

Abstract

Two different thyme species (Thymus vulgaris L. and Origanum majorana L.), sage (Salvia officinalis L.) and lavender (Lavandula officinalis L.) extracts were tested against pre-adult stage of Potato tuber moth-PTM [(Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae)], which is an important quarantine pest. Each plant extracts prepared with ethanol were applied to larvae and eggs in three different concentrations 3%, 5 and 10 ml/L. In the egg treatments at the highest concentration (10% ml/L), inhibition rate was observed in Lavander and T. vulgaris 73.7%, in O. majorana 67.5% and in sage 66.2%, respectively. Results indicated that the mean number of hatching eggs were highly decreased as concentration increased, the highest decreased was observed with treated 10% concentration. of lavender and T. vulgaris. Observation were for 7 days. In the insecticidal toxicity study of against the larval stage, mortality were determined at the highest concentration (10% ml/L) in O. majorana 91.2%, Lavander 90%, T. vulgaris 87%, and Sage 83.7% at the end of 7th day. It was also determined that the larval mortality rate was higher with the increasing of extracts of 4 different plant depending on time. As a result, in this study, ovicidal toxicity of plant extracts was recorded against to on egg stage and it was that impact of insecticidal against to on larval stage also.