Crambe, Crambe abyssinica Hochst., as a Flea Beetle Resistant Crop (Coleoptera: Chrysomelidae)

Abstract

Choice tests were conducted in the field and laboratory to determine the feeding preference of the flea beetle, Phyllotreta cruciferae (Goeze), for oilseed rape, Brassica napus L., and crambe, Crambe abyssinica Hochst. Flea beetle feeding (primarily abaxial) was significantly higher on oilseed rape than on crambe. Although flea beetle presence on crambe was not inhibited, feeding pits were often shallow and smaller, suggesting the presence of a gustatory deterrent in crambe tissue. Mechanical tissue damage had no effect on flea beetle feeding on oilseed rape, but it caused an increase in the incidence of feeding on crambe. Because the preference for damaged crambe was manifest only after long exposure to the plants, release of volatile attractants by the plants in response to damage was unlikely. The area of feeding in damaged crambe remained slight despite the increased incidence of feeding, suggesting that damage does not notably compromise resistance in crambe.