Tag Archives: Entomosporium maculatum

What not to plant……….

Now that the US horticulture industry is a nationwide enterprise diseases are able to spread from one coast to the other within a few seasons. In the good ol’ days, when plants were grown locally, this problem was less severe and diseases could be contained or stopped before they became a national epidemic.

This has created a “DO NOT PLANT” list in my mind every time I see one of these plants at a nursery. I have also learned to read labels to see if the location of production is listed.

Here are a few of the plants that are current on my Do Not Plant list:


Rose Rosette Virus: Rose rosette disease is a viral rose disease spread by a tiny insect. The virus is specific to roses with Rosa multiflora being its primary host. The disease is sometimes called witches’ broom because of the way it causes new shoots to grow straight up and close together in broom-shaped clusters. There is no cure. Once a plant is infected it should be burned to destroy the virus and the plant.


Downy mildew: The spore causes impatiens’ leaves to turn spotted and yellow, and eventually fall off. Infected plants left in the garden can infect the soil, leading to a long-term problem. The plants wither away. It’s such a devastating disease that many growers are not growing Impatiens this year.


Leaf spot, caused by the fungus Entomosporium maculatum, is a widespread and destructive disease of red tip (Photinia fraseri), loquat (Eriobotrya japonica), India hawthorn (Rhaphiolepis indica), some pear cultivars (Pyrus sp.) and several other members of the rose family. This disease is most damaging to plants in the landscape and nurseries during periods of cool, wet weather and when active growth is occurring.

Below: Entomosporium leaf spot on a redtip photinia.
Tiny, circular, bright red spots on both the upper and lower surfaces of young expanding leaves are the first symptoms of Entomosporium leaf spot. Numerous small spots may coalesce into large maroon blotches on heavily diseased leaves. Leaf spots on mature leaves have ash brown to light gray centers with a distinctive deep red to maroon border. Tiny black specks, spore producing bodies of the fungus, can often be observed in the center of each leaf spot

So I guess the moral of my short story would be that if a plant is in vogue and everyone is planting it everywhere- you might want to be careful. In a few years some disease or pest might just be following it around the country just waiting for the right time to strike!



Filed under General Gardening