Crop & Pest Report


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Scout for Cereal Aphids (06/18/20)

Cereal aphids have arrived in ND with the help of the strong southerly winds!

Cereal aphids have arrived in ND with the help of the strong southerly winds! IPM Scouts just started to see cereal aphids in wheat last week at one site in Bottineau County, and more fields this week in the southeast area. No reports of cereal aphids were found in barley yet.

Scouting for cereal aphids is easy and should begin at stem elongation. Look on the undersides of leaves and near the base of the plant for the tiny ⅛-inch long, greenish and pear-shaped aphids. Aphids can be winged or wingless. The most common species in ND are the English grain aphid, bird cherry oat aphid and greenbug. When temperatures are in the low to mid-80s F, conditions are favorable for fast reproduction. Cereal aphids usually have several generations in ND before dying off in the fall.

Continue scouting for cereal aphids for the next month in wheat (spring, durum and winter), oat and barley, or until the crop gets past the end of heading stage.

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 percent of infested plants (incidence) with one or more aphids. The economic threshold is 85% of the plants infested and 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 of barley yellow dwarf (BYDV), which can stunt plants and reduce yield. A common symptom of BYDV is yellowing of the leaf, often the flag leaf, from the tip back toward the stem. No insecticides are necessary after the onset of flowering, since the negative impacts of cereal aphid feeding are reduced (no yield loss).



Janet J. Knodel

Extension Entomologist


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