ALLELOCHEMICALLY MEDIATED HOST-RESISTANCE TO THE COLORADO POTATO BEETLE, LEPTINOTARSA-DECEMLINEATA (SAY) (COLEOPTERA, CHRYSOMELIDAE)

Several wild species of potato and tomato are highly resistant to the Colorado potato beetle, Leptinotarsa decemlineata (Say), and allelochemicals have been associated with resistance in some of these such as 2-tridecanone in the glandular trichomes of Lycopersicon hirsutum f. glabaratum C.H. Mull and leptine glycoalkaloids in the leaves of Solanum chacoense Bitt. We determined the glycoalkaloid compositions of leaves from two newly recognized resistant species, S. neocardenasii Hawkes and Hjerting and S. pinnatisectum Hawkes. Glycoalkaloids occurring at high concentrations in S. neocardenasii (tomatine and a new glycoalkaloid, solanocardenine) and S. pinnatisectum (tomatine) may be at least partially responsible for their resistance to Colorado potato beetle. The role of glycoalkaloids and glandular trichomes in conferring resistance to the Colorado potato beetle in wild Solanum species is discussed.