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.
![collard edema Symptoms of edema on collard leaf. Note the off-color appearance of leaf surface.](https://plant-pest-advisory.rutgers.edu/wp-content/uploads/2013/06/collard-edema-300x225.jpg)
Symptoms of edema on top side of
collard leaf.
Note the off-color appearance of leaf surface.
![collard edema 2 Edema, bottom side of collard leaf. Note the irregular, 'corky appearance caused bythe rupture of leaf cells.](https://plant-pest-advisory.rutgers.edu/wp-content/uploads/2013/06/collard-edema-2-300x225.jpg)
Edema, bottom side of collard leaf.
Note irregular, “corky” appearance due to
leaf cell rupture.