Female navel orangeworm,Amyelois transitella(Walker), laid the greatest number of eggs on mature or green almond fruits, stems or leaves of an almond tree, or filter paper substrates treated with a water extract of larval frass. Similar acetone and acetonitrile extracts of frass also stimulated oviposition on some tests on some substrates as did extracts of macerated larvae prepared with any of the 3 solvents, but to a lesser extent. Phenyl propionate inhibited oviposition on mature almonds.