Poplar shoot blight is quite common around the Dakotas and Minnesota and is not a problem on mature trees. Young trees may benefit from an early season application of a fungicide containing chlorothalonil . Application at bud break and 10-14 days later should minimize the effects of the disease. However, by the time the disease is observed it is too late for treatment. The humid, wet weather that has occurred over much of the state this spring has been very favorable for powdery mildew development.
Powdery mildews can be severe on lilac, phlox, roses, current and Monarda.
They also occur on many other hosts. Powdery mildews are easily recognized by the dusty, powdery appearance they cause on the leaves of their hosts. When severe, powdery mildews can cause deformation of the leaves. Roses and other plants that have green stems may also be infected on that plant part. Powdery mildews will also colonize flowers and buds on rose, causing color breaks on flowers and bud abortion.