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 Rhizoctonia and Fusarium crown rots and summer black stem on alfalfa; Phytophthora root/stem rot, frogeye, and downy mildew on soybean; black shank, frogeye leaf spot, angular leaf spot, and frenching on tobacco.
On fruit, herb and vegetable crops, we have seen crown gall on grape; cedar-apple rust, thread blight, and frogeye leaf spot on apple; downy mildew on basil; bacterial crown rot on parsley; black rot on collard and kale; gummy stem blight, Cercospora leaf spot, downy mildew, and powdery mildew on cantaloupe; downy mildew on pumpkin; powdery mildew on winter squash; gummy stem blight on watermelon; bacterial speck, early blight, Septoria leaf spot, leaf mold, and Pythium root rot on tomato; and bacterial soft rot on sweet corn.
On ornamentals and turf, we have diagnosed Pythium root rot, Alternaria leaf spot, and web blight on chrysanthemum; Rhizoctonia root rot on daisy and begonia; bacterial spot on begonia; Cercospora leaf spot on hydrangea and sourwood; Verticillium wilt on redbud; Guignardia leaf blotch on horsechestnut; spot anthracnose and powdery mildew on dogwood; take-all on bentgrass; and brown patch and anthracnose on fescue.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians