Club root
Plasmodiophora brassicae

• Roots are swollen into large spindle shaped tumor like galls
• Leaves turn pale yellow, wilt during hot, sunny days, and recover at night
• Young plants may die
• Common in wet soils with a low pH (acidic)
• More information on Club Root

Cabbage maggot
Delia radicum

• Chewing and tunneling in roots is present
• Feeding may cause deformed roots
• Plants may appear yellow and wilted
• Maggots may be present; they are carrot-shaped, legless, and cream colored
• Present in early May – mid June

• More information on Cabbage Maggot

Black rot
Xanthomonas campestris

• Yellow V-shaped lesions develop on margin of leaves, the point of the v follows a vein towards the base of the leaf
• As infection continues, leaves wilt, turn yellow and eventually turn brown and die
• Black veins can be seen in infected leaves, petioles and stems
• Disease favored by hot, humid conditions
• More information on Black Rot

Downy mildew
Peronospora parasitica

• Angular yellow spots on leaves that eventually grow into tan papery areas with a yellow border
• Fuzzy white to gray fungal growth can be seen on the underside of the leaves
• Dark brown to black sunken area on the upper half of the radish root, center of root remains white
• Skin on the root may be rough, corky and cracked
• Common in cool wet weather
• More information on Downy Mildew

Cabbage aphid, green peach aphid, and turnip aphid
Brevicoryne brassicae, Myzus persicae, Lipaphis erysimi

• When large numbers are present, leaves can become yellow
• 1/16-1/8 inch long, soft-bodied and pear-shaped
• Aphids are present throughout the growing season
• More information on Aphids