Conopomorpha sinensis Bradley (Lepidoptera: Gracilariidae) is the most destructive borer pest of litchi, Litchi chinensis Sonn., and longan, Euphoria longan (Lour.) Steud. (both Sapindaceae) fruits in Southeast Asia and southern China. In this study, ethanol extracts from leaves of Lantana camara L. (Verbenaceae), Wedelia chinensis (Osbeck) Merr. (Compositae), Eupatorium odoratum (L.) King and Robinson (Compositae), Bauhinia purpurea L. (Leguminosae), and Melaleuca leucadendron L. (Myrtaceae) were chosen to evaluate the oviposition deterrent effect and ovicidal activity of non-host plant extracts on C. sinensis. The plant extracts from L. camara, W. chinensis, and E. odoratum caused oviposition deterrent behavior by the adult C. sinensis. The ethanol extracts from L. camara were found to have the maximum effective deterrence (i.e., 93.5% in the choice test, and 73.6% in the no-choice test). This led to the lowest oviposition activity index (−0.9) and the highest reduction level of egg-laying (3.3 eggs daily per female). In the assessment of ovicidal activity of the plant extracts on C. sinensis, W. chinensis caused diminished hatching rate (< 60%) at concentrations of 0.01 g·mL⁻¹ and 0.1 g·mL⁻¹. These encouraging results suggest that secondary substances from L. camara and W. chinensis have effective oviposition deterrent and ovicidal activities to C. sinensis, and these substances have potential as plant protectants for litchi and longan fruits.