Plant Disease Diagnostic Lab Highlights

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 anthracnose, common leaf spot, and Lepto leaf spot on alfalfa; common rust on corn; brown spot on soybean; Pythium root rot and Botrytis blight on hemp; Pythium root rot, black shank, tomato spotted wilt, and transplant shock on tobacco.

Figure 1. Striking symptoms of “popcorn disease” of mulberry. This unusual disease is so-named because the fungus-infected fruits resemble clusters of unpopped popcorn (Photo: Julie Beale, UK)

Figure 1. Striking symptoms of “popcorn disease” of mulberry. This unusual disease is so-named because the fungus-infected fruits resemble clusters of unpopped popcorn (Photo: Julie Beale, UK)

Figure 2. Fungal survival structures called “sclerotia” replace the normal tissues inside mulberry fruits (Photo: Julie Beale, UK)

Figure 2. Fungal survival structures called “sclerotia” replace the normal tissues inside mulberry fruits (Photo: Julie Beale, UK)

On fruit and vegetable samples, we have diagnosed anthracnose fruit rot and Phomopsis leaf blight on strawberry; Phomopsis dieback, Fusicoccum canker, and anthracnose fruit rot on blueberry; black rot on grape; cedar-apple rust, and frogeye leaf spot on apple; angular leaf spot, Rhizoctonia root/stem rot, and white mold on bean; bacterial wilt on cucumber; bacterial blight and Stemphyllium leaf spot on onion; black dot, early blight, lesion nematode, and Rhizoctonia and Pythium root rots on potato; bacterial spot, bacterial canker, early blight, Septoria leaf spot, and catfacing on tomato.

Ornamental and turf samples included rust on hollyhock; anthracnose on daylily; Pythium root rot on phlox; anthracnose on oak; Phyllosticta leaf spot on maple; popcorn disease on mulberry (Figures 1 & 2); tip blight and Dothistroma needle blight on pine; Rhizosphaera needlecast on spruce; brown patch and red thread on fescue; cottony blight and Pythium root dysfunction on bentgrass.

 

By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians

Posted in Plant Disease Diagnostic Lab