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 Lepto leaf spot on alfalfa; lance nematode (Figure 1) and root lesion nematode on corn seedlings; and frogeye leaf spot on tobacco transplants.

Figure 1. Female lance nematode and nematode egg from corn seedling roots. The rounded tail, sclerotized head, and prominent bulbs at the base of the mouthpart (stylet) are characteristic of this nematode. Plant stunting is the most common symptom observed on plants infested with lance nematode (Photo: Brenda Kennedy, UK)

On fruit and vegetable crops, we have diagnosed spur blight on blackberry; cane blight on raspberry; Phomopsis leaf blight, Rhizoctonia fruit rot, cold injury, and spider mite injury on strawberry; cane girdler injury on grape; leaf curl on peach; fire blight and frogeye leaf spot on apple; and tomato spotted wilt virus on tomato.

On landscape and turf samples, we have seen Pythium root rot on petunia; Volutella blight on pachysandra; leaf miner injury and Volutella canker/dieback on boxwood; Coniothyrium canker on rose; Pestalotia twig blight on arborvitae; Kabatina twig blight on juniper; Phomopsis dieback on ornamental cherry; Rhizosphaera and Stigmina needle casts, Dothistroma needle blight and spider mite injury on spruce; Diplodia tip blight and Dothistroma needle blight on pine; anthracnose and scale infestation on tuliptree; Botryosphaeria dieback on oak; and red thread on fescue.

 

By Julie Beale and Brenda Kennedy, Plant Disease Diagnosticians

 

 

Posted in Plant Disease Diagnostic Lab