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, Diplodia leaf streak, gray leaf spot, and Physoderma leaf spot on corn; summer black stem/leaf spot and potato leafhopper injury on alfalfa; Pythium and Rhizoctonia root rots, Cercospora leaf spot, broad mite and russet mite injury on hemp; Phytophthora root/stem rot on soybean; angular leaf spot, frogeye, black shank, soreshin, tomato spotted wilt, and weather fleck on tobacco.
On fruit, herb, and vegetable crops, we have diagnosed anthracnose, spur blight, and red-necked cane borer injury on blackberry; Phytophthora crown rot on rhubarb; bacterial spot on cherry; Phytophthora root/crown rot on peach; cedar-apple rust, frogeye leaf spot, and fire blight on apple; Cercospora leaf spot and variegated cutworm injury on hops; bacterial crown rot on artichoke; cucumber mosaic virus on celery; anthracnose and Pythium root rot on cucumber; angular leaf spot on pumpkin; bacterial spot on pepper; Septoria leaf spot, ripe rot, and yellow shoulders on tomato; and gummy stem blight on watermelon.
On ornamentals and turf, we have diagnosed Pythium root rot on chrysanthemum and miscanthus; Volutella blight on pachysandra; boxwood blight, Volutella canker, Macrophoma dieback, and leaf miner injury on boxwood; black root rot on holly; Botryosphaeria canker on lilac; Phytophthora root/crown rot on viburnum; spider mite and bagworm injury on arborvitae; Seiridium canker on Leyland cypress; anthracnose (Monostichella) on maple; Rhizosphaera needle cast and Stigmina needle blight on spruce; anthracnose on walnut; Curvularia leaf spot and Pythium root dysfunction on perennial ryegrass; and brown patch on fescue.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians