The following plant disease highlights from the University of Kentucky Plant Disease Diagnostic Laboratories represent recent sample submissions from field crops, fruit, vegetables, and ornamentals.
Diagnostic samples of agronomic crops from the past week have included common rust on corn; Lepto leaf spot and potato leafhopper injury on alfalfa; gray leaf spot on foxtail millet; leaf streak on orchardgrass; angular leaf spot, frogeye leaf spot, Pythium root rot, black shank, soreshin, Fusarium wilt, tomato spotted wilt, alfalfa mosaic virus, boron deficiency, temporary phosphorus deficiency, potassium deficiency, symptoms related to low soil pH, soil compaction, and transplant shock on tobacco.
On fruit and vegetable crops, we have diagnosed black rot on grape; cedar-apple rust on apple; black knot on plum; southern blight on bean; anthracnose on cucumber; anthracnose and Alternaria leaf blight on cantaloupe; Pythium and Rhizcotonia root rots and bacterial leaf spot on pepper; powdery mildew on squash; Septoria leaf spot, bacterial leaf spot, early blight, and tomato spotted wilt on tomato; and Cercospora leaf spot on watermelon.
On landscape and turf samples, we have seen boxwood blight on boxwood; Gymnosporangium rust on serviceberry; scab on crabapple; anthracnose on oak; Pythium and Rhizoctonia root rots on fir; Swiss needle cast on Douglas fir; Rhizosphaera needle cast on spruce; anthracnose and brown patch on fescue.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians