What is making my rose bush so lifeless? Knockout rose, 5 years First noticed...
What is making my rose bush so lifeless? Knockout rose, 5 years First noticed around June Symptoms worsened with summer Full sun Soil problems - Clay, but roses seem to grow better than anything else No pesticide or fertilizer Rose is scentless and flowering August 17
The damage to the roses looks like it was subject to feeding by the rose slug. Go to our website and view photos http://extension.umd.edu/learn/rose-slug
It is neither a slug or caterpillar (even though it looks like one), but the larvae of a species of sawfly. Adults are very small flying insects related to wasps. The larva is small and “slug-like” in appearance. It feeds mostly from the underside of the leaf eating many holes and causing considerable damage. Severe rose slug feeding will stunt the rose’s growth and flowering. Apply insecticidal soap or horticultural oil to upper and lower leaf surfaces. Follow all label directions and do not apply during high temperatures.