Edema is being reported in some brassica crops. Edema is often expressed as off-color swellings or galls that appear on leaves and stems. Edema develops when epidermal cells hold excessive water due to a slowing of evapotransporation when hot, muggy days are followed cooler, wetter weather. Edema develops because the plant takes in more water (due to a high soil moisture content) than it can get rid of causing cells to rupture which results in the blistering of the leaves.
Symptoms of edema on top side of
collard leaf.
Note the off-color appearance of leaf surface.
Edema, bottom side of collard leaf.
Note irregular, “corky” appearance due to
leaf cell rupture.
