Yield Responses of Potatoes to Defoliation by the Potato Flea Beetle (Coleoptera: Chrysomelidae) in Manitoba

Abstract

Individually caged potato plants, of the cultivars ‘Norland’ and ‘Russet Burbank’, were grown in field plots in Manitoba. For ‘Norland’ trials, adult potato flea beetles, Epitrix cucumeris (Harris), were maintained in cages at constant multiples of naturally occurring field densities for the duration of the growing season. ‘Russet Burbank’ trials were performed in the same way except that, in half of the treatments, larval and adult Colorado potato beetles, Leptinotarsa decemlineata (Say), were maintained during thee early part of the growing season. In the absence of Colorado potato beetle injury, both cultivars exhibited compensatory to slightly overcompensatory yield responses at low levels of potato flea beetle feeding. No yield loss was observed at up to 65 and 190 flea beetles per plant for ‘Norland’ and ‘Russet Burbank’, respectively; above this density, yield was inversely proportional to flea beetle density. When ‘Russet Burbank’ plants had sustained early season Colorado potato beetle injury, there was no compensation by plants, and yield was inversely proportional to density throughout the range of flea beetle treatments.