By Janet J. Knodel
Extension Entomologist
Our first cereal aphids were detected in McHenry County in the NC area of North Dakota at sub-economic level, 14% incidence, on durum wheat by the IPM Scout, Jacee Aaseth. Scouting over the next month will be important for the wheat (spring, durum and winter), oat and barley.
Cereal Aphids Arrive
Our first cereal aphids were detected in McHenry County in the NC area of North Dakota at sub-economic level, 14% incidence, on durum wheat by the IPM Scout, Jacee Aaseth. Scouting over the next month will be important for the wheat (spring, durum and winter), oat and barley. Cereal aphids are blown into North Dakota from the south, and usually have several generations before dying off in the fall. Scouting should begin at stem elongation and continue up through the heading stage of wheat. For a scouting protocol, walk a Z or W pattern across the field and inspect 20 randomly selected stems at 5 sites for cereal aphids. Calculate the average number of aphids per stem or the percent of infested plants (incidence) with one or more aphids. The economic threshold is 12-15 aphids per stem or 85% incidence prior to the completion of heading. Heavy infestations of cereal aphids can reduce grain quality (protein and test weight). In addition, cereal aphids are good vectors barley yellow dwarf (BYDV), which can stunt plants and reduce yield! Symptoms of BYDV are yellowing of leaves (often the flag leaf) and stunting of plants. After the onset of flowering, the negative impacts of cereal aphid feeding are reduced (no yield loss).
