The effects of plant extracts from eucalyptus, lemon balm, soapwort and Persian hogweed against Phthorimaea operculella (Zeller) under laboratory conditions

Regarding the harmful side effects of chemical insecticides, currently the uses of the plant extracts have been considered. The potato tuber moth, Phthorimaea operculella Zeller is an important pest of potato in the fields and stores especially in tropical and subtropical regions of the world. The damage of this pest in stores is more serious than the fields. In this research the extracts of four different medicinal plants including: eucalyptus, Eucalyptus camaldulensis Dehn., lemon balm, Melissa officinalis L., Acanthophyllum bracteatum Boiss. and rampion, Heracleum persicum Desf. Were studied in the growth chamber set at 25±2˚C, 65±5% RH and photoperiod of 14 light and 10 dark hours. In the study of ovicidal effects, the LC50 in eucalyptus and rampion were 7.07 and 6.95%, respectively. In the study of first instar larval penetration, it was found that all the extracts were significantly lower than the control. In oviposition inhibition test, it was found that all the plant extracts have significantly reduced the oviposition of the potato tuber moth. In the fumigant effect experiments, there was no significant difference between the plant extracts and the control. Therefore it was concluded that none of the plant extracts have fumigant effects on different life stages of the potato tuber moth. Therefore, it can be concluded that eucalyptus and rampion extracts can be used to control the composting of potato tuber moth due to the appropriate controlling effects on this pest.