Spots on my Oregon grape
What is going on with my Oregon grape?
Multnomah County Oregon
Spots can be the result of different agents, including fungi, insects, slugs, even hail or drought. If you would describe the size, shape, color, and location ofthe holes on the leaf, whether they penetrate all the way through the leaf and how many leaves are affected, it would really help us to help you. Pictures would be great - of the affected leaves and of the whole plant and its location in your garden. Any information would welcome.
Thank you for your response. These Oregon grapes are in partial sun. We’ve lived here for 4.5 years and this is the first time I’ve noticed a problem. In the fall I dug up blackberries around the Oregon grapes.
The spots are dark brown and fizxy on the underside
The spots on your Oregon grape look like fungal infections. To confirm take a few affected leaves to your Multnomah County Master Gardener Office (2701 NW Vaughn Street, Suite 450 [4th floor Montgomery Building]; Portland OR 97210;email@example.com; 503-445-4608; open M-F 10am-2pm). They can look at the spots under magnification. The fuzzy areas are probably producing spores.
Fungal infections are caused by wet conditions. Try to keep your Oregon grape plants dry by providing good air circulation around the plants and use watering devices that don't wet the leaves, like soaker hoses or drip. Remove affected leaves. You can use horticulture oil like neem oil on the leaves to halt the infection. This article has additional information, Oregon Grape (Berberis aquafolium) Leaf Spot https://pnwhandbooks.org/plantdisease/host-disease/oregon-grape-berberis-aquifolium-leaf-spot.