Bioefficacy of leaf extracts from Pouzolzia zeylanica (L.) Benn against diamondback moth plutella xylostella in Viet Nam

In Viet Nam, Pouzolzia zeylanica (L.) Benn is a native plant and has been demonstrated its applicability as a medical plant. Additionally, Pouzolzia zeylanica was used to control fly larvae during food processing due to insecticidal activity. We optimized the extraction of Pouzolzia zeylanica by ethanol at different conditions: concentration, the ratio of solid (material) - liquid (ethanol volume) (mg/ml) and the extraction time (hour). Results indicated that extraction yield was effected by all of the factors. The optimized extraction yield was 6.85% (Y) with ethanol concentration at 96 percent ethanol (Z1), the ratio solid to liquid is 1: 25 (mg/ml) (Z2) and extraction time is 4 days (Z3). We tested the efficiency of leaf extracts from Pouzolzia zeylanica and antifeedant activity against diamondback moth Plutella xylostella at different leaf extract concentrations. Results indicated that 80% mortality induced by those compounds was recorded on Plutella xylostella second instars at 30% leaf extract concentration and had significant difference compared to the control (P=0.0000); the leaf extract affected the ratio of pupation, adult emergence and antifeedant activity of P. xylostella (P=0.0000). The obtained results promise a potential of using Pouzolzia zeylanica as biopesticide in Viet Nam