The temperatures during the last week and the forecasted temperatures for next week will potentially encourage rapid pea aphid population growth. As a reminder, pea aphid (Figure 1) population growth is highest when temperatures are around 70 °F but are decreased during higher temperatures. In addition, many areas have already observed large pea aphid populations in 2026 (Figure 2).
Although many fields have been cut recently, pea aphids can still readily recolonize alfalfa. If pea aphid populations reach thresholds, they can be managed using foliar insecticides. However, those populations need to be closely monitored to ensure they don’t rapidly exceed the threshold and cause yield reductions.
