Chemical Composition of the Essential Oil of Eucalyptus procera Dehnh. and Its Insecticidal Effects Against Two Stored Product Insects

Abstract

Botanical essential oils have been successfully used in controlling insect pests. In the present study, insecticidal activity of essential oil extracted from the leaves of messmate stringybark [Eucalyptus procera Dehnh. (Myrtales: Myrtaceae)] were investigated through contact and fumigant toxicity against the cowpea weevil [Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)] and the red flour beetle [Tribolium castaneum Herbst (Coleoptera: Tenebrionidae)]. Chemical analysis of the essential oil by Gas chromatography-Mass spectrometry proved 1,8-cineole (45.0 %), α-pinene (28.6 %) and viridiflorol (5.7 %) were major constituents of the oil. The essential oil comprises 98.3 % terpenic compound including 31.4 % monoterpene hydrocarbons, 55.8 % oxygenated monoterpenes, 2.2 % sesquiterpene hydrocarbons and 8.9 % oxygenated sesquiterpenes. Results showed that C. maculatus and T. castaneum were very susceptible to the essential oil of E. procera in both contact and fumigant bioassays. 24 h-LC values were 0.124 and 0.129 μl/ cm2 in the contact toxicity and 11.722 and 13.9 μl/l air in the fumigant toxicity for C. maculatus and T. castaneum, respectively. LT50 values were 16.137 h for T. castaneum and 13.644 h for C. maculatus at the highest tested concentrations (24 μl/l air for T. castaneum and 20 μl/l air for C. maculatus). Results of present study indicated that the essential oil of E. procera can be considered as anatural resource for C. maculatus and T. castaneum management.

Key words:

• Eucalyptus procera
• essential oil
• phytochemistry
• stored product insects
• toxicity