Abstract:
Plant allelochemicals from essential oils have recently received considerable attention in pharmaceutical, cosmetic and agricultural sectors due to their biodegradability and low toxicity. This study analyzed
the chemical composition and bioinsecticidal activity of essential oils of Pinus caribaea Morelet var. hondurensis
needles. Thirty-nine (39) organic compounds were identified using gas chromatography/mass chromatography
and gas chromatography, and the most abundant components were limonene (38.6%), α-pinene (27.6%), bor-
neol (6.7%) and myrcene (3.5%). The chemical composition of the needles was dominated by monoterpene
hydrocarbons (77.2%) followed by oxygenated monoterpenes (12.0%), sesquiterpene hydrocarbons (4.7%)
and then lastly oxygenated sesquiterpenes (1.7%). In fumigant toxicity, 100% mortality was recorded at
10 μL/ml for bean weevils after 2 hours of exposure whereas the same concentration caused 100% mortal-
ity of maize weevils after 5 hours of exposure. In repellency bioassay using aliquots of acetonic essential
oils, 100% repellence was recorded in bean weevils after 60 minutes of exposure while the same concentra-
tion (8 μL/ml) gave 100% repellence activity in maize weevils after 150 minutes. The essential oils showed
higher insecticidal activity against bean weevils than maize weevils. Based on the results of this study, pine
needles could be a suitable source of green insecticides for control of maize and bean weevils in stored food
products