Michigan State University Extension
Ornamental Plants plus Version 2.0 - 00000237
01/01/98
Wilt starts with brown spotting and wilting at the base of the plant then extends upwards. Avoid over-watering and long periods of excessive humidity.
Stem rot develops quickly from well-defined yellow lesions that later become dark brown. Entire plants may collapse and die within 2 to 4 days. Destroy badly diseased plants.
Pad decay affects the cactus segments or pads. Cut out and destroy diseased parts and avoid wounding.
Slimy collar rot causes a soft, slimy, black rot at the base of the plant. There is no effective control.
Soft rot or gray mold causes tissue discoloration then rotting and collapse of the upper surface. Plant tissues undergo a slimy disintegration. Under moist conditions, a gray mold develops on the surface of diseased parts. Remove diseased tissue.
Bud fall is the premature dropping of flower buds. Possible causes are, lack of nourishment, excessive nitrogen, excessive soil dryness, over-watering, and syringing with cold water.
Corky scab causes irregular, rusty or corky spots on stems. Older parts of the plant may have many spots while young shoots have none. Severe attacks may destroy entire shoots. Mild attacks may decrease flower production. Epidermal cells dry then the epidermis breaks open and curls. Increase light exposure and decrease humidity.
Glassiness symptoms are dark green translucent spots. Slight pressure crushes the epidermis then the tissue beneath rapidly turns black. The shoots above the infection may be killed. Mild attacks cause corky layers or spots. Increase light exposure and decrease humidity.