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.
Recent agronomic samples have included gray leaf spot, northern leaf blight, brown spot (Physoderma), and southern rust on corn; Phytophthora root/stem rot, “wet feet” and compaction, and brown spot (Septoria) on soybean; frogeye leaf spot, angular leaf spot, target spot, Pythium root/stem rot, soreshin, tomato spotted wilt virus, frogeye, alfalfa mosaic virus, manganese toxicity, and weather fleck (ozone injury) on tobacco.
On fruit and vegetable crops, we have seen Botryosphaeria canker on blueberry; Sphaerulina leaf spot and Phytophthora root rot on raspberry; water core on apple; fire blight on Asian pear; Cercospora leaf spot on bean; Rhizoctonia stem rot and Alternaria leaf spot on cabbage; anthracnose, bacterial wilt, gummy stem blight, and belly rot (Rhizoctonia) on cantaloupe; bacterial soft rot on lettuce; bacterial spot on pepper; early blight, Septoria leaf spot, Pythium root rot, and tomato spotted wilt virus on tomato; powdery mildew, Plectosporium blight, and angular leaf spot on squash/zucchini; anthracnose and gummy stem blight on watermelon.
On ornamentals and turf, we have diagnosed Pythium and Rhizoctonia root rots and southern blight on chrysanthemum; Pythium root rot on vinca; powdery mildew and anthracnose on dogwood; Cytospora canker on cherry; leaf blister on oak; anthracnose and take-all on bentgrass; and dollar spot on bluegrass.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians