Brevianamide A, and its photolysis product brevianamide D from Penicillium viridicatum, and ochratoxin A from P. verrucosum were assayed against two lepidopterous pests, Spodoptera frugiperda and Heliothis virescens. Ochratoxin A and brevianamide A were potent antifeedants against larvae of both species at 1000 p.p.m., and the latter retained activity at 100 p.p.m. Ochratoxin A caused 100% mortality at 10 p.p.m. against S. frugiperda, and brevianamide D was more effective than brevianamide A at reducing pupal weight. This is the first report of biological activity for brevianamide D.