Plant Disease Diagnostic Lab Highlights

The following plant disease highlights have been compiled from samples submitted to the University of Kentucky Plant Disease Diagnostic Laboratories from July 2-8, 2019.

Diagnostic samples of agronomic crops have included Northern leaf blight and common rust on corn; Rhizoctonia root rot on alfalfa; anthracnose and rust on fescue; anthracnose and leaf streak on orchardgrass; Cercospora leaf spot, powdery mildew, and Pythium root rot on hemp; Phytophthora root/stem rot and brown spot (Septoria) on soybean; angular leaf spot, frogeye, target spot, black shank, and soreshin on tobacco.

On fruit and vegetable crops, we have diagnosed Phytophthora root/crown rot on blueberry; anthracnose on blackberry; bacterial spot on cherry; Phytophthora crown rot and deep planting on peach; Cercospora leaf spot on bean; Cercospora leaf spot on cantaloupe; anthracnose on cucumber; Pythium rot and bacterial spot on pepper; Sclerotinia rot on pumpkin; Fusarium wilt, Rhizoctonia root rot, black dot root rot, southern blight, Septoria leaf spot, and buckeye rot on tomato; gummy stem blight and anthracnose on watermelon.

Figure 1.  Symptoms of tomato spotted wilt virus on dahlia.  This thrips-vectored virus has a wide host range, including vegetable, agronomic, and ornamental crops (Photo: Julie Beale, UK).

On ornamentals, we have diagnosed Rhizoctonia root rot on petunia; Phytophthora blight on catharanthus; bacterial leaf spot and Pythium root rot on chrysanthemum; tomato spotted wilt virus on dahlia (Figure 1); boxwood blight, Volutella canker, and Macrophoma dieback on boxwood; anthracnose on beech, oak, and yellowwood; Verticillium wilt on magnolia, lilac, and redbud; tip blight on pine; Rhizosphaera needle cast on spruce; and brown patch on bluegrass.



Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians



Posted in Plant Disease Diagnostic Lab
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