Survival and development of Heliothis virescens (Lepidoptera: Noctuidae) larvae on isogenic XXXX lines with different levels of alkaloids.

@entity286 @entity13708 @entity1239 @entity26401 @entity28522
Levels of @entity26401 were measured in 18 @entity286 , @entity286 ., entries from three parental isolines ('NC 95', 'SC 58', and 'Coker 139'), grown at Tifton, GA, Florence, SC, and Oxford, NC, in 1991. Levels of alkaloids in bud leaves (first fully unfolded leaf below the apical leaf bud) were negatively correlated to natural infestation ratings of @entity13708 larvae, Heliothis virescens (F.), 7 wk after transplanting. For artificially infested bud leaves at Oxford, there was a significant negative correlation between levels of total alkaloids and larval weights after 1 wk of feeding. In 1992, four entries from the 'NC 95' @entity28522 were grown at Oxford, and samples for alkaloid analyses were taken every 2 wk at several leaf positions on each plant. During weeks 4, 8, 12, and 16, second instar @entity13708 were caged on individual, intact leaves inside perforated plastic bags in the field. The survival and development of @entity13708 larvae after 1 wk were negatively correlated with levels of alkaloids at the various leaf positions. Larvae survived better and grew faster on the bud leaves of each entry where alkaloid levels were lower than they did on leaves further down the stalk where alkaloid levels were higher. More larvae survived on the lower leaves of the low alkaloid lines than on the lower leaves of the high alkaloid lines. Even moderate increases in @entity26401 had negative effects on @entity13708 survival and development. @entity1239 constituted >97% of the @entity26401 in the 'NC95' @entity28522 each year.
