The emulsifiable concentrate (EC) and wettable powder (WP) of Piper aduncum and Tephrosia vogelii mixed formulations were tested for their activities in the laboratory and their effectiveness in the field against cabbage pest Plutella xyostella. Cabbage leaves soaked in six different mixed formulation concentrations were tested against second instar larvae of P. xylostella and observed until the larvae reached fourth instar stage. From the survived larvae, growth and development, antifeedant effects were recorded. Field efficacy test was based on LC95 value of formulations from laboratory test result. The experiment used a randomized block design with 5 treatments and 3 replications to determine the insecticide effectivity against populations of P. xylostella larvae. The results showed that the EC and WP mixed formulations have insecticidal activity against P. xylostella larvae, with LC95 value of 0.35% and 0.37%, respectively. The highest antifeedant effect on EC mixed formulation was 85.01% and WP mixed formulation was 86.23%. Both mixed formulations also slowed the development of larvae when compared with control. Field effication result showed that applications of EC mixed formulation were able to restrain the population of P. xylostella, with effectivity value of 71.06%. Insecticide effectivity value of EC mixed formulation was higher than WP mixed formulation and Bacillus thuringiensis formulation.