Branch Dieback of Juniper and Arborvitae

After several years of relatively few problems of junipers and arborvitae, we've had a resurgence in the shoot blights. The most common is phomopsis tip blight, which affects the new growth. New growth is susceptible until it loses its lighter color. Control consists of removing infected areas, and spraying new growth with protectant fungicides until it gets the dark green color. Symptoms are a "shepherd's crook" shape to the dead tips and the small black dots of the fungal fruiting bodies

Kabatina and Cercospora blights affect older needles of evergreens. Kabatina blight is not as common, and it is not controlled by fungicides. Cercospora blight tends to infect the older needles on lower branches first. The appearance of branches is having only the new growth at the branch tips being green. Repeated applications of fungicides will have some effect on Cercospora. There are varieties resistant to these diseases, but you can't find one resistant to all three.

Posted by John Fulton at 10:26 AM |