Brassica Diseases
Leaf Spot
When Leaf Spot or Blotch is prevalent, the infected leaves turn brown, wither, and die. The lower 30 to 40 percent of a severely damaged plant is often completely defoliated. Uncut plants are usually affected to a greater extent.
Anthracnose
Spot causing fungal disease which causes summer depression of grasses. The lesions are at first water-soaked small spots and then expands to faint reddish brown to orange. Fungal tissues are produced in the center of the old lesion and looks black and moldy. Orange masses of spores are formed on the lesion under wet conditions and they disperse by wind and rain. The disease often occurs from the end of a rainy spring season into summer.
Brown Stripe
The spot causing fungal disease prohibits the seed production. The lesion are brown to purple brown, short line shaped that appears between the leaf veins at first. They gradually expand to and fuse one another. The whole leaf becomes ash white and killed. The spores which look like small black molds are produced on the old lesion, and they disperse and spread. The pathogen can also affect other grasses like Timothy.
Powdery Mildew
The lesions are at first small and white to gray moldy in the leaf appearing before the rainy season. When the disease advances, the entire plant body looks like it’s being covered with white powder. The white powder are spores and they disperse by wind and rain. When it rains, they are washed off and yellowish brown, irregular-shaped lesions appear. The disease prefers the cool condition and occurs when it is cloudy and insufficient sunshine continues.
Rust
Occurs from late spring to early summer. The disease produces reddish brown, oval swelling lesions on the surface of the leaf and sheaf. The surface of the lesion tears when maturing and disperses spores. The disease is typically found on the back of the leaf and becomes yellow to brown.