Thelechitonia trilobata is regarded as a troublesome weed that grows to form a dense blanket over the soil preventing the growth of other crops in farmland. Although the plant is regarded as a notorious, invasive plant, its chemical composition and biological potential have not been reported. The essential oil was isolated from the fresh leaves of T. trilobata using hydrodistillation. alpha-Pinene (21.6%), alpha-phellendrene (21.0%), limonene (12.8%) and germacrene D (7.5%) were the major constituents of the oil. The essential oil was screened against agricultural pests. The anti-tick properties were tested on Ripicephalus e. ervertsi found on sheep, while repellency, fumigation, and contact toxicity tests were carried out with maize weevils. Except for the contact toxicity test, all other bioassays gave positive results.