Client dropped off a sample of 20 yr old cotoneaster. There are plants approximately a block and half in length of these same plants. The center plants are showing this condition. The neighbors did spray a few weeks ago. Can you please ID the problem and recommend measures to help the plants? Thank you!
Lake County South Dakota
This is hard to tell from the pictures but this might be fireblight on the cotoneaster. The symptoms of darkening and curling leaves are consistent with those expressed by this bacterial disease. If it is fireblight my recommendation is this fall after the plants go dormant cut the infested plant to within 3 inches of the ground and destroy the clippings. This usually removes the disease. The entire row can be treated this way and it will come back as a nice hedge next spring. However, disinfect the pruners when moving from diseased to healthy plants to avoid spreading the infection next year.