Early fall seeding has higher incidence than late fall or early winter seeding. Risk is higher with low plant populations. Prolonged summer drought may indicate greater risk. Symptoms are yellow older leaves with asymmetrical younger leaves dwarfed, crinkled, and rolled upward and inward. Control suggestions are high plant populations, broadleaf weed control near fields before and after planting and delayed fall planting dates.
Incidence is nearly uniform across fields.
Resistance could probably be developed in spinach. High light intensity after several days of cloudy weather may trigger rapid symptom development and rapid quality loss. Symptoms are mild chlorotic spotting on interveinal areas, most often on the leaf tips of older and middle-aged leaves. From a distance, the canopy may have a bronze cast. Alternaria invades yellowed leaf tissue, resulting in black lesions with red-orange halos.