Biological activity and chemical characteristics of essential oils from the indigenous plant in Palestine

Abstract

New pesticides based on plant extracts and essential oils (EO) are the modern approach to control insect pests and diseases and replacing synthetic pesticides. Therefore, a preliminary screening of nine indigenous plants containing essential oil for antifungal and insecticidal impacts on selected microorganisms and insect pests was evaluated during 2018-19 at Kadoorie Agricultural Research Center (KARC), Palestine Technical University. The biological properties of the plant extracts and EO were tested in vitro. Results showed that clove, thyme and eucalyptus oil significantly inhibited the growth of A. niger, B. cinerea, A. flavus, P. ultimum, P. digitatum and F. oxysporum 24 and 48 hr post-application. EC50 and EC90 values were significantly the lowest for eucalyptus, thyme then clove. LC50 and LC90 values against green peach aphid and two-spotted red spider mite were calculated from log-dose probit mortality regression. EO bioassay on aphid showed no significant impact of aphid mortality among all the EO, but a significant effect on the two-spotted red spider mites mortality. Mustard, sage and bitter-cucumber oil applications have high mortality on aphid, while mustard, mint and sesame oil application have high mortality on the two-spotted red spider mite. EO showed no significant impact on plant enzyme activities as in expression values of PPO and POX. The biological activity of the EO investigated on several microorganisms, and insect pests suggested that clove, eucalyptus and thyme showed the highest antifungal activities, while mint, mustard and sesame have the highest insecticidal and acaricidal activities.