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.
Diseases diagnosed on agronomic crops during the past week have included gray leaf spot and southern corn rust on corn; Pythium root rot, leaf streak, and anthracnose on orchardgrass; Rhizoctonia web blight and summer black stem on alfalfa; web blight and poor nodulation on soybean; angular leaf spot, black shank, soreshin, frogeye leaf spot, target spot, and low pH symptoms on tobacco.
On fruit and vegetable samples, we have diagnosed black rot on grape; Phytophthora root/crown rot on blueberry; Phytophthora crown rot on rhubarb; cedar-apple rust, sooty blotch/flyspeck, frogeye leaf spot, and plum curculio damage on apple; Fusarium stem rot on bean; bacterial spot and Pythium root/crown rot on pepper; scab on potato; angular leaf spot, powdery mildew, downy mildew, Microdochium blight, root knot nematode, squash vine borer, and spider mite injury on pumpkin; early blight, Septoria leaf spot, leaf mold, and stinkbug injury on tomato; Cercospora leaf spot and powdery mildew on watermelon.
Ornamental and turf samples included Rhizoctonia web blight, Fusarium wilt, and Pythium root rot on chrysanthemum; Cercospora leaf spot and powdery mildew on rose; bacterial leaf spot on cherry; anthracnose on oak; Rhizosphaera needlecast on spruce; Verticillium wilt on smoketree and sumac; brown patch on fescue; gray leaf spot on perennial ryegrass; Pythium blight, Pythium root dysfunction, take-all, and heavy thatch buildup on bentgrass.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians