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Sixteen species of Nicotiana were examined for resistance to second instar larvae of the tobacco horn-worm, Manduca sexta (L.). The tests were designed so as to discriminate between antibiosis and nonpreference. High levels of antibiosis resistance were observed in several wild species such as N. gossei and species in the Repandae section. Several other species, such as N. excelsior, showed antibiosis that appeared to be due to a different mechanism than the alkaloid-trichome exudate based resistance of the above species. The data indicate that these species of Nicotiana may be used as a new source of resistance to larvae of M. sexta. RESUME D'especes sauvages de Nicotiania comme nouvelle source de resistance du tabac a Manduca sexta La resistance aux chenilles de second stade de Manduca sexta L. a ete examinee chez seize especes de Nicotiana. Les essais ont ete concus pour distinguer absence d'appetance et antibiose. Plusieurs especes sauvages comme N. gossei et les especes de la section Repandae ont presente un niveau eleve d'antibiose. D'autres especes, comme N. excelsior ont presente une antibiose vraisemblablement due a un mecanisme different de la resistance des especes precedentes provoquee par un exsudat alcaloide des trichomes. Les resultats indiquent que ces especes de Nicotiana peuvent etre utilisees comme nouvelle source de resistance aux chenilles de M. sexta.