The following plant disease highlights from the UK Plant Disease Diagnostic Laboratories represent recent sample submissions from field crops, fruit, vegetables, and ornamentals during October.
Diagnostic samples of agronomic crops included summer black stem and anthracnose on alfalfa; gray leaf spot on corn; sudden death syndrome, Diaporthe pod/stem blight, anthracnose, and charcoal rot on soybean.
On fruit and vegetable samples, diagnoses included blister spot on apple; Coccomyces leaf spot on dwarf sour cherry; Cercospora leaf spot on bean; scab and Fusarium dry rot on potato; scurf on sweetpotato; anthracnose (fruit lesions) on pumpkin; and severe whitefly infestation on (greenhouse) tomato.
On ornamentals, we diagnosed powdery mildew on coreopsis; Cercospora leaf spot on poinsettia and hydrangea; boxwood blight (Calonectria) and Volutella canker on boxwood; Botyrosphaeria canker on rhododendron; Armillaria root rot on hydrangea, dogwood and redbud; Verticillium wilt on maple; bacterial scorch on oak; Rhizosphaera needlecast on spruce; and Cytospora canker and rust on willow.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians