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.

Recent diagnostic samples of agronomic crops have included Rhizoctonia crown rot on corn; target spot on tobacco transplants.

On fruit and vegetable crops, we have diagnosed Phomopsis leaf blight, Botrytis fruit rot, spider mite injury, and the black root rot complex on strawberry; leaf curl, Leucostoma canker, and stinkbug injury (fruit) on peach; cedar-apple rust on apple; Fusarium crown rot on asparagus; Pythium root rot on multiple crops (i.e., broccoli, pepper, tomato, and watermelon); bacterial soft rot on garlic; Fusarium wilt, spider mite injury, leaf mold, and tomato spotted wilt virus on tomato.

On landscape and turf samples, we have seen Volutella blight on pachysandra; leaf miner injury and Volutella canker/dieback on boxwood; Coniothyrium canker, Pseudocercospora leaf spot, powdery mildew, and sawfly injury on rose; Dothistroma needle blight and needle rust on pine (Figures 1 & 2); and red thread on fescue.

Figures 1. Needle rust disease alternates between pines and plants in the aster family, such as asters and goldenrod. White, raised structures of the needle rust fungus form along pine needles in spring (Photo: Brenda Kennedy, UK).

Figure 2. Needle rust fungal structures have ruptured to reveal orange spores. Severe infection may result in browning and premature needle drop; most of the time, however, the effect on pines is minimal (Photo: Brenda Kennedy, UK).

 

By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians

 

 

Posted in Plant Disease Diagnostic Lab