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 Aphanomyces seedling root rot, spring black stem/leaf spot, and common leaf spot on alfalfa; Pythium root rot and target spot on tobacco transplants.
On fruit, nut and vegetable samples, we have diagnosed anthracnose fruit rot and Phomopsis leaf blight on strawberry; anthracnose and black rot on grape; cedar-apple rust, fire blight, and frogeye leaf spot on apple; bacterial leaf spot, Leucostoma canker, and hail injury on peach; anthracnose and phylloxera galls on pecan; Pythium root rot on numerous vegetable crops, including bean, cantaloupe, watermelon, pepper, tomato, and okra; bacterial spot on pepper; ozone injury on cucumber; early blight, Botrytis leaf blight and fruit decay, timber rot (Sclerotinia), Fusarium wilt, tomato spotted wilt virus, blossom end rot, and catfacing on tomato.
Ornamental and turf samples included Pythium root rot on petunia; white mold (Sclerotinia) on hellebore; anthracnose crown/stem rot on phlox; black root rot on holly and boxwood; powdery mildew (Figure 1), fungal canker, and rose sawfly feeding injury on rose; anthracnose on ash and oak; Phomopsis canker/dieback on flowering cherry; Rhizosphaera needlecast and Stigmina needle blight on spruce; and red thread on turfgrass.
By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians