The following plant disease highlights have been compiled from samples submitted to the University of Kentucky Plant Disease Diagnostic Laboratories from May 1 to May 20, 2019.
Diagnostic samples of agronomic crops have included Pythium and Rhizoctonia damping off, anthracnose, and Lepto leaf spot on alfalfa; leaf streak on orchardgrass; Pythium root rot, target spot, cutworm damage, and cold injury on tobacco; russet mite infestation, powdery mildew, and Sclerotinia stem rot on hemp.
On fruit and vegetable crops, we have diagnosed anthracnose crown rot on strawberry; spur blight and orange rust on blackberry; Phytophthora root/crown rot on raspberry; Phomopsis dieback on haskap; anthracnose on fig; bacterial canker on cherry; Sclerotinia stem rot on broccoli; Pythium root rot on okra; bacterial spot on pepper; bacterial spot, bacterial pith necrosis, leaf mold, Botrytis blight, tomato spotted wilt, and timber rot (Sclerotinia) on tomato.
On ornamentals and turf, we have diagnosed broad mite injury and Pythium root rot on dahlia; Botrytis blight on begonia; downy mildew on impatiens; Botrytis blight, broad mite injury, and iron toxicity on geranium; cold injury and thrips damage on petunia; Sclerotinia stem rot on calibrachoa; bacterial leaf spot on hydrangea; boxwood leaf miner and Volutella canker on boxwood; cedar-hawthorn rust on hawthorn; anthracnose on ash and maple; scab on crabapple; Phyllosticta and Pestalotiopsis needle blights on juniper; Dothistroma blight and needle rust on pine; Dothistroma and Stigmina needle blights, Rhizosphaera needle cast, and spider mite injury on spruce; suspected herbicide injury on various woody ornamental species; red thread on fescue; Pythium root dysfunction on bentgrass and perennial ryegrass; and large patch and root decline (Gaeumannomyces) on bermudagrass.
Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians