Yield Losses in Winter Grains Caused by Cereal Aphids (Homoptera: Aphididae) in South Dakota

Abstract

Yield losses in ‘Rough Rider’ winter wheat, Triticum aestivum L., and ‘Cougar’ winter rye, Secale cereale L., caused by feeding of Schizaphis graminum (Rondani), Rhopalosiphum padi (L.), and Macrosiphum avenae (F.) were each measured for 3 yr in South Dakota fields. Caged plots were artificially colonized with aphids for 10 d when plants were in three different growth stages; losses in components of yield were measured at harvest. Greatest losses of yield were caused when aphids fed during the seedling (2-3 leaf) stage in autumn; mean densities of 25-30 aphids per stem caused reductions of 50% in some components of yield at this stage. Lower yield losses were recorded for similar aphid population densities when they fed in spring during the boot stage (immature in florescence invested in leaf sheath), and no losses were observed when aphids fed on mature (dough stage) plants. Schizaphis graminum and R. padi were more damaging than M. avenae at similar population densities. Winter wheat was more vulnerable than rye to yield losses caused by aphid feeding.