Richard Thurston

ALKALOID SECRETION BY TRICHOMES OF NICOTIANA SPECIES AND RESISTANCE TO APHIDS

Alkaloids are secreted by trichomes of the seven Nicotiana species tested. Nicotine, the major alkaloid constituent, was identified in the secretions from all species and anabasine, and probably nornicotine, from two species. Aphids are killed by contact with these secretions, and resistance to the green peach aphid, Myzus persicae, results from this mortality.

TOXICITY OF NICOTIAN A GOSSEI DOMIN TO MYZUS PERSICAE (SULZER)1

Resistance in Nicotiana species to the green peach aphid appears to result from the production of a toxic material produced by the aerial parts of the plant. Materials exuded from the leaf hairs which are transferred to glass micro beakers are toxic to several species of aphids. The symptoms of such poisoning resemble those of nicotine poisoning, but resistance does not appear to be correlated with the amount of nicotine in the leaf.