The following is an updated version of an older article … The next 4-5 weeks is the time to consider making a foliar application for aphids in wheat. I’ve discussed the potential value of managing aphids to prevent the spread of barley yellow dwarf virus (BYDV) in a previous article. A late-winter, foliar insecticide application, at least on wheat not having an insecticide seed treatment, has shown a consistent yield benefit in my testing over the last five years (figure below).
I do not think the timing of this application is especially critical, BUT it must be made before aphids have become well established in the field. Otherwise, you’ve missed the opportunity to prevent the transmission of BYDV. You are likely too late if aphid populations already exceed 6-8 aphids per foot of row. Insecticides recommended for the control of aphids in wheat are listed in UT’s insect control recommendations for wheat.