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 crown rot, Fusarium crown rot, and summer black stem on alfalfa; frogeye leaf spot and downy mildew on soybean; angular leaf spot, black shank, frogeye leaf spot, and target spot on tobacco; and gray leaf spot on millet.
On fruit and vegetable crops, we have seen black rot and crown gall on grape; cedar-apple rust on apple; fire blight on pear; downy mildew on basil; Pythium root rot on cabbage; black rot on collard and kale; downy mildew on cucumber and pumpkin; downy mildew on kale; Phytophthora crown rot on rhubarb; anthracnose, bacterial speck, and Septoria leaf spot on tomato; and bacterial fruit blotch, anthracnose, and gummy stem blight on watermelon.
On ornamentals and turf, we have diagnosed Alternaria leaf spot and Pythium root rot on chrysanthemum; Rhizoctonia root and stem rot on begonia and petunia; Pythium root rot on daisy; Phyllosticta leaf spot on fern; bacterial soft rot on iris; powdery mildew on peony; blight on chestnut; Cytospora canker on juniper; Phyllosticta leaf spot on maple; white pine root decline on pine; Verticillium wilt on redbud; Rhizosphaera and Stigmina needle cast on spruce; Cylindrosporium leaf spot on walnut; and take-all on bentgrass.
By Sara Long, Plant Disease Diagnostic Assistant, and Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians