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 have included leaf streak on orchardgrass; Pythium and Rhizoctonia root rots on clover; magnesium deficiency and decline from shallow planting on corn; potassium deficiency on soybean; Pythium root rot on hemp; angular leaf spot, Pythium root rot, blackleg, black shank, soreshin, tobacco mosaic virus, temporary phosphorus deficiency, and transplant shock on tobacco.
On fruit, nut and vegetable crops, we have diagnosed anthracnose fruit rot on blueberry; black rot and anthracnose on grape; cane blight on blackberry; cedar-apple rust and plum curculio injury on apple; cedar-quince rust and fire blight on pear; bacterial spot on peach; anthracnose on pecan; ashy stem blight and southern blight on bean; white mold and blackleg (Phoma) on cabbage; bacterial wilt on cucumber, squash and melon; Cercospora leaf spot on garlic; Pythium root rot and bacterial spot on pepper; Cercospora leaf spot on squash; wireworm injury on sweet corn; Septoria leaf spot, bacterial spot, bacterial speck, Pythium root rot, Rhizoctonia root/stem rot, Fusarium wilt, root knot nematode, and tomato spotted wilt virus on tomato; and Pythium cottony leak on watermelon.
On ornamentals and turf, we have diagnosed Pythium root rot on chrysanthemum; Pythium root rot, Rhizoctonia root/stem rot, and Phytophthora blight on annual vinca; Rhizoctonia root rot on creeping phlox; Volutella blight on pachysandra; Botryosphaeria dieback and obscure scale on holly; scab on crabapple; shot-hole spot (Blumeriella) on cherry; Marsonnina leaf spot on poplar; anthracnose, leaf blister, potato leafhopper injury, and Verticillium wilt on maple; anthracnose, powdery mildew, Monochaetia leaf spot, and horned oak gall on oak; yellow poplar weevil injury on tuliptree and magnolia; Rhizosphaera needle cast and Stigmina needle blight on spruce; Seiridium canker on Leyland cypress; Diplodia tip blight on pine; take-all patch and anthracnose on bentgrass; and brown patch on fescue.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians