cole crop diseases

Alternaria Leaf Spot

Alternaria leaf spot-Lesions of Alternaria leaf spot on cole crops are typically round with a concentric ring structure. I have not found this disease to be very important on crops in the field in most years. But it can be devastating in transplant greenhouses. 
Figure 1. Alternaria leaf spot lesion on a broccoli transplant. Figure 1. Alternaria leaf spot lesion on a broccoli transplant.
Figure 2. Alternaria leaf spot lesions of several different sizes can be observed. Figure 2. Alternaria leaf spot lesions of several different sizes can be observed.
Figure 3. The roughly round area of diseased broccoli transplants observed here represents a focus of disease. Alternaria leaf spot probably started on a transplant in the center of this area and spread to surrounding seedlings. Figure 3. The roughly round area of diseased broccoli transplants observed here represents a focus of disease. Alternaria leaf spot probably started on a transplant in the center of this area and spread to surrounding seedlings.
Figure 4. Alternaria leaf spot lesions on a mature broccoli leaf. Figure 4. Alternaria leaf spot lesions on a mature broccoli leaf.
Figure 5. Alternaria leaf spot on kale. Figure 5. Alternaria leaf spot on kale.

Black rot

Black rot-The importance of black rot on a cole crops depends in part on when the disease becomes prevalent. If the disease doesn’t become prevalent until late in the season, yield loss will probably be light. However, if black rot affects the crop at an early stage, yield loss may be considerable. Black rot may also be important in the transplant greenhouse. Typical symptoms include V-shaped lesions on the leaf margin. 
Figure 1. Black rot has caused the lesions on this cabbage plant. Figure 1. Black rot has caused the lesions on this cabbage plant.
Figure 2. Close up of black rot on cabbage leaf. Figure 2. Close up of black rot on cabbage leaf.
Figure 3. Typical V-shaped lesion of black rot on cabbage leaf. Figure 3. Typical V-shaped lesion of black rot on cabbage leaf.
Figure 4. Initial lesion of black rot on cabbage. Figure 4. Initial lesion of black rot on cabbage.
Figure 5. Initial lesions of black rot on nearly mature cabbage. Figure 5. Initial lesions of black rot on nearly mature cabbage.
Figure 6. A row of cabbage severely affected by black rot. Figure 6. A row of cabbage severely affected by black rot.
Figure 7. Black rot on broccoli transplant. Figure 7. Black rot on broccoli transplant.
Figure 8. Black rot on nearly mature broccoli. Figure 8. Black rot on nearly mature broccoli.

Wirestem

Wirestem-The above ground symptoms of wirestem may be the decline or wilt of the plant. Once unearthed, the characteristic narrowing of the lower stem and upper portion of the root system can be observed. This portion of the stem/root system is often discolored as well. 
Figure 1. Wirestem of broccoli. Figure 1. Wirestem of broccoli.
Figure 2. Wirestem of broccoli. Figure 2. Wirestem of broccoli.