Tomato plants in Nigeria were subjected to foliar sprays of Bacillus thuringiensis subsp. kurstaki (formulated as Dipel and Thuricide) and Baculovirus heliothis (Elcar), to which carbaryl, plus the adjuvants Tenac and Gustol were on occasion added, to test their effectiveness against Helicoverpa armigera (Hübner) and other lepidopterous larvae. H. armigera larvae were found susceptible to both pathogens. The 0·5 kg/ha and the 1·0 kg/ha applications of Bacillus thuringiensis gave good field control of the larvae, similar to that of carbaryl at 1·5 kg/ha. Bacillus and virus were compatible but not significantly more effective when combined than when applied separately. Combinations of bacillus and virus with carbaryl were also not significantly more effective than the pathogens applied separately. B. thuringiensis at 0·5 kg/ha applied with carbaryl at 0·5 kg/ha was as good as carbaryl at 1·5 kg/ha. Gustol and Tenac did not significantly increase the effectiveness of the pathogens.