Rust causes small, brown blisters on under surfaces of leaves. Areas around blisters turn light green, leaves curl and die. Bud rot causes growing tips and buds to soften and turn brown. Affected buds do not open. Septoria leaf spot causes leaves to turn brown, yellow, or reddish, then black spots develop.
Infection starts at the bottom of the plant and spreads upward.
Wilting Verticillium wilt is caused by a fungus that lives in the soil. Diseased plants usually wilt, turn brown, become stunted, and produce poor flowers. If the plants do not wilt, areas between veins of the leaves turn yellow. Stunting Chrysanthemums stunt, aster yellows, and leaf nematode infection prevent normal growth. They cannot be controlled.