Abstract: Field trials evaluating the potential of the entomopathogenic nematode Steinernema carpocapsae and the feasibility to combine nematodes with Bacillus thuringiensis for sustainable control of the diamondback moth (DBM) Plutella xylostella were conducted in cabbage cultivated in the province Probolinggo, east Java and Indonesia. A single use of 0.5 million S. carpocapsae m−2 applied with a surfactant-polymer-formulation containing 0.3% xanthan and 0.3% Rimulgan® achieved a significant reduction of the insects per plant with >50% control after 7 days. Even 14 days after the application about 45% control was recorded and dead larvae containing nematodes were found. No significant effects were recorded when the formulation was compared with nematodes applied in water or with a surfactant alone. This was attributed to high humidity in the experimental area at the end of the rainy season and a microclimate in the cabbage heads favouring nematode survival. Weekly applications of B. thuringiensis (Turex®) or alternating applications of Turex® and the nematodes achieved >80% control. The application of both biological agents together every second week reached insignificant lower efficacy (70%). Nematodes can be used to substitute ineffective chemical insecticides and alterations with B. thuringiensis can prevent the further development of resistance against the bacterial control agent.