INSECTICIDAL ACTIVITY OF FIVE ETHANOLIC EXTRACTS AGAINST COMMON CUTWORM, Spodoptera litura (Fabricius) (LEPIDOPTERA: NOCTUIDAE)

Ethanolic extracts from five Philippine plants, namely: Alpinia pyramidata Blume, Lantana camara L., Plectranthus amboinicus (Lour.) Spreng. (=Coleus amboinicus Lour.), Curcuma longa L. and Catharanthus roseus (L.) G.Don were evaluated in the laboratory for their insecticidal activities against third larval instar of common cutworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). All the five ethanolic extracts were toxic against cutworm (LD50 = 48.44-80.19 µg/mL acetone) when applied topically at 72h after treatment, while L. camara extract was the most toxic (LC50 = 126.01 µg/g larval body weight) when applied through leaf residue film method. Ethanolic extract from P. amboinicus provided the highest antifeedant activity at 250 µg/g. At 1000 µg/g, all ethanolic extracts showed repellency comparable with Cymbopogon nardus. Ethanolic extracts from A. pyramidata and Cu. longa showed remarkable insect growth regulatory activities against cutworm expressed by a high number of abnormal pupae, and adults, respectively. Meanwhile, ethanolic extracts from L. camara, P. amboinicus, Ca. roseus and A. pyramidata provided short life span of 7-8 days when applied on cutworm larvae; a normal adult lived for about nine days when provided with 10% honey solution as food. In view of their overall pesticidal properties, crude ethanolic extracts from the five plants could be studied further and develop formulation for control of cutworm.