FEEDING-BEHAVIOR AND SURVIVAL OF COLORADO POTATO BEETLE, LEPTINOTARSA-DECEMLINEATA (SAY), LARVAE ON SOLANUM-BERTHAULTII HAWKES AND AN F-6 SOLANUM-TUBEROSUM L X S-BERTHAULTII HYBRID

Newly hatched Leptinotarsa decemlineata larvae were less likely to initiate feeding on Solanum berthaultii than on S. tuberosum. Among larvae that fed there was no difference in the time to initiation of feeding; however, the duration of the initial feeding bout was less on S. berthaultii than on S. tuberosum. Larvae spent less time feeding and more time walking on S. berthaultii than on S. tuberosum. All larvae caged on S. tuberosum fed within 24 hours, but larvae were less likely to feed on a F6 S. tuberosum X S. berthaultii hybrid and least likely to feed on S. berthaultii. Lack of feeding during the first 24 h was highly correlated with mortality at 72 h. Whether or not larvae feed within the first five minutes of being placed on a leaflet is a reliable predictor of larval mortality at 72 h and is a useful test for determining the susceptibility of plants to feeding by L. decemlineata. The amount of trichome exudate accumulated on the tarsi over a 72 h period is correlated with resistance. Resistance of S. berthaultii to neonate L. decemlineata is characterized by a refusal to initiate feeding and a reduced feeding rate by larvae that do feed.