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 stress from compaction and magnesium deficiency on corn; Lepto leaf spot on alfalfa; brown stripe on orchardgrass; and Pythium root rot on tobacco.
On fruit, nut, and vegetable crops, we have seen Phylloxera galls on grape and pecan leaves; fire blight, thread blight, and crown gall on apple; bacterial stalk rot on sweet corn; bacterial wilt on cucumber; Phytophthora blight on pepper and squash; Rhizoctonia root/stem rot on sage; early blight, Septoria leaf spot, leaf mold, blossom end rot, Rhizoctonia and Pythium root rots, root knot nematode, and Fusarium wilt on tomato.
On ornamentals and turf, we have diagnosed Pythium root rot on petunia; Rhizoctonia root/stem rot on ginger; leaf/flower gall on azalea; Cercospora leaf spot on hydrangea; powdery mildew, anthracnose, and spot anthracnose on dogwood; rust on smoketree; anthracnose on lilac, elm, and maple; leaf blister on oak; fire blight on pear; and dollar spot on bentgrass.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians