Pale yellow upper corn leaves abound across Iowa as corn enters the teens of growth stages with some tasseling. These once sun-starved leaves entrapped in the whorl by more mature leaves will wave for a day or more above rapidly growing crop canopies before turning green. Although incidences seem more numerous than in other years, the symptom is not unusual. We reported on it last year occurring at about the same growth stages – tenth to twelfth leaf - and have an article posted on our website that discusses earlier-season situations.