INFLUENCE OF TILLAGE SYSTEM, PLANTING DATE, AND OILSEED CRUCIFERS ON FLEA BEETLE POPULATIONS (COLEOPTERA, CHRYSOMELIDAE)

Cultural practices (tillage, planting date) were examined for their ef fect on flea beetle, Phyllotreta cruciferae (Goeze), populations in th ree species of oilseed crucifers-Brassica napus L., B. rapa L., and Cr ambe abyssinica Hochst. No-till appeared to reduce flea beetle densiti es when compared with conventional tillage. The greater structural div ersity of the no-till plots might be interfering with host plant locat ion. Earlier plantings had significantly more flea beetles per plant t han later plantings. The Brassica crops yielded higher densities of be etles compared with crambe, supporting earlier reports of crambe resis tance.