Pests are one of the constraints in agricultural crops, such as the army worm (Spodoptera exigua), that is considered as one of the most harmful pests in the vegetative phase. In this work, ethanolic leaf extracts of common plants Senna sophera (L.) Roxb., Syzygium cumuni, and Annona squamosa Linn. in Llanera, Nueva Ecija, Philippines were prepared and the phytochemical constituents were detected. Direct spraying of the extracts was done to test the effectiveness of the biopesticides. Results showed that the extracts have varying effectivity as biopesticide against Spodoptera exigua and can be related to the chemical constituents present in the extracts. Considering the results from this investigation, the easy availability and effectiveness of these natural pesticides can be developed as alternatives to conventional synthetic pesticides.