The following plant disease highlights have been compiled from samples submitted to the University of Kentucky Plant Disease Diagnostic Laboratories from July 2-8, 2019.
Diagnostic samples of agronomic crops have included common rust, southern rust, northern leaf blight, Diplodia leaf streak, gray leaf spot, and stinkbug injury on corn; anthracnose on sorghum; summer black stem/leaf spot and potato leafhopper injury on alfalfa; Pythium and Rhizoctonia root rots and Septoria leaf spot on hemp; Phytophthora, Rhizoctonia and Pythium root/stem rots and brown spot (Septoria) on soybean; angular leaf spot, frogeye, black shank, and potassium deficiency on tobacco.
On fruit and vegetable crops, we have diagnosed Phytophthora root/crown rot on raspberry; white drupelet disorder on blackberry; brown rot, scab, and split pit disorder on peach; cedar-apple rust on apple; Rhizoctonia root/stem rot and Cercospora leaf spot on bean; Cercospora leaf spot and angular leaf spot on cucumber; Pythium and Rhizoctonia root rots on pepper; bacterial soft rot on summer squash; Pythium root rot and Septoria leaf spot on tomato; gummy stem blight on watermelon.
On ornamentals and turf, we have diagnosed web blight (Rhizoctonia) on calibrachoa; Volutella blight on pachysandra; boxwood blight, Volutella canker, and Macrophoma dieback on boxwood; Phytophthora root/crown rot on juniper; anthracnose on beech, elm, and dogwood; Verticillium wilt on elm, maple, tulip poplar, and redbud; Botryosphaeria dieback and potato leafhopper injury on maple; Rhizosphaera needle cast and Stigmina needle blight on spruce; and anthracnose and Pythium root dysfunction on bentgrass.
Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians