EFFECT OF SOLANUM GLYCOALKALOIDS ON POTATO-APHID, MACROSIPHUM-EUPHORBIA

Macrosiphum euphorbiae, also known as the potato aphid, is a potato vi rus vector, associated with decreased tuber production. Feeding, toxic ity, and reproductive effects of the major potato glycoalkaloids (alph a-chaconine and alpha-solanine), their common aglycone (solanidine), a nd a nonpotato glycoalkaloid (alpha-tomatine) and its aglycone (tomati dine) on M. euphorbiae were studied. As expected, neither alpha-chacon ine nor alpha-solanine had a strong lethal effect on the aphid, but al pha-chaconine stimulated feeding at low concentrations. Both aglycones were deterrent and lethal at high concentrations and, like alpha-chac onine and alpha-tomatine, they delayed the appearance and decreased th e number of nymphs.