Extraction, Chemical Composition and Insecticidal Activities of Linn. Leaf Essential Oils against , and .

Storage pests and the food spoilage they cause are problems of great concern. Using essential oil obtained from different plants as an insecticide against these storage pests can be considered an environmentally friendly pest management option. Linn. (family Verbenaceae) is a flowering species, and is also a noxious weed that can proliferate well in nearly all geographical habitats. A biopesticide derived from the essential oil extracted from this plant can offer an effective solution for controlling storage pests. The goal of this study is to extract and analyse the chemical composition of essential oil obtained from leaves, and assess its effectiveness as a bioactive substance against three storage pests: , , and . The yield of essential oil extracted from leaves was about 0.24 ± 0.014%. By employing the GC-MS technique, the major phytochemicals contained in leaf essential oil were identified as caryophyllene (69.96%), isoledene (12%), and ɑ-copaene (4.11%). The essential oil exhibited excellent fumigant toxicity (LC of 16.70 mg/L air for , 4.141 mg/L air for and 6.245 mg/L air for at 24 h), contact toxicity (LC of 8.93 mg/cm for , 4.82 mg/cm for and 6.24 mg/cm for after 24 h) along with effective repellent activity towards the test insects. In addition, the oil showed no significant phytotoxicity on the germination of paddy seeds. This presents the potential to utilize a weed in developing a biopesticide for effectively managing stored product insects because of its strong bioactivity.