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 diagnostic samples of agronomic crops have included zinc deficiency and thrips injury on corn; spring black stem on alfalfa; Pythium root rot, target spot, and severe aphid infestation with sooty mold on tobacco transplants.
On fruit and vegetable crops, we have diagnosed anthracnose on grape; brown rot on cherry; black knot on plum; cedar-apple rust, fire blight, plum curculio injury, and rosy apple aphid on apple; Pythium root rot and bacterial leaf spot on pepper; tomato spotted wilt, leaf mold, and flea beetle feeding on tomato; and Pythium root rot on watermelon.
On landscape and turf samples, we have seen Phoma dieback on vinca; Volutella canker/dieback on boxwood; anthracnose on lilac; Coniothyrium canker, powdery mildew, black spot, and sawfly injury on rose; cottony camellia scale on holly; scab, frogeye leaf spot and cedar-apple rust on crabapple; Verticillium wilt on sumac; anthracnose on oak; Rhizosphaera needle cast on spruce; Seiridium canker on Leyland cypress; and red thread on fescue.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians