We are starting to see continued increases in leaf hopper populations in alfalfa fields. Also while scouting soybean fields I was also finding leaf hoppers. Keep an eye on alfalfa fields as the nymphs can cause damage pretty quickly. Once you start to see yellowing or "burn", yield has already been reduced. The threshold for 4-6 inch tall alfalfa is 50 leaf hoppers per 100 sweeps. Soybeans in the seedling stage are most susceptible to injury. If you see plant damage and average 8 leaf hopper per sweep, control may be necessary.