Losses in Yield in Spring Wheat in South Dakota caused by Cereal Aphidst12

Abstract

Losses in yield of ‘Protor’ hard red spring wheat, Triticum aestivum L., due to feeding of Schizaphis graminum (Rondani), Macrosiphum avenae (F.), and Rhopalosiphum padi (L.) were measured in 1975, 1976, and 1977 in South Dakota fields. Caged plots (1 m long × 0.6 m wide × 0.8 m high) were artificially colonized with aphids for 10 days when plants were in the seedling, boot, and mature (dough) stages. All losses in components of yield (number of heads, number of kernels, total kernel weight, 100 kernel weight) were measured at harvest. The most marked losses in yield were caused when aphids fed during the seedling (2-leaf) stage; mean densities of 25–30 aphids/stem caused substantial (60%) reductions in some components of yield at this stage. Less loss in yield components was observed due to aphid infestation at the boot stage and no losses in yield (P>0.05) were recorded when plains were mature, even at densities of 50–70 aphids/stem. S. graminum and R. padi were more damaging than M. avenae at similar population densities.