Yellow Leaves on Broccoli
The lower leaves of my broccoli plants turn yellow. I have had to grow the plants in the same location for several years. Could this be cabbage yellows?
Heat and water stress as well as cabbage yellows and black rot can cause the damage you described. Mulching and proper watering keep the soils cool and moist reducing environmental stress. If this isn't the case it could be cabbage yellows or black rot. Yellows is a fungal disease that causes leaves to yellow and brown from the bottom of the plant up. The inside of the infected stems are yellow-black and the midrib of the leaf may be curved. Yellows is less of a problem now due to the introduction of so many resistant cultivars. Always select fusarium resistant cultivars. Black rot is caused by a bacteria The symptoms first appear as a triangle of yellow at the tip of the leaves with the point of the V facing toward the stem. The lesions expand and eventually the leaf wilts. The inside of black rot infested stems are black and may be accompanied by a yellow slime. Grow broccoli, cabbage and other cole crops in a new location for several years. You may need to grow them in containers if your gardening space is limited.