Plant essential oils from twenty plant species were tested for their insecticidal activity against larvae of Lycoriella ingenua using a fumigation bioassay. Good insecticidal activity (>90%) against larvae of L. ingenua was achieved with essential oils of caraway seed (Carum carvi), lemongrass (Cymbopogon citratus), mandarine (Citrus reticulate), nutmeg (Myristica fragrans), cade (Juniperus oxycedrus), spearmint (Mentha spicata), cumin (Cuminum cyminum) and thyme red (Thymus vulgaris) oils at 30×10-3 mg/㎖ air. Among them, caraway seed, spearmint, cumin and thyme red essential oils were highly effective against L. ingenua at 20×10-3 mg/㎖ air. Analysis by gas chromatography-mass spectrometry led to identification of 4, 9, 8 and 17 compounds from caraway seed, spearmint, cumin and thyme red oils, respectively. These compounds were tested individually for their insecticidal activities against larvae of L. ingenua, and compared to the toxicity of dichlorvos. Carvacrol, thymol, linalool, cuminaldehyde, p-cymen, terpinen-4-ol and carvone was effective at 10×10-3 mg/㎖. The insecticidal activity of dichlorvos was 60% at 10×10-3 mg/㎖. Effects of four selected plant essential oils on growth of Pleurotus ostreatus were also investigated.