Hello everybody,
Since a few years the rose disease, Elsinoe rosarum also called Sphaceloma rosarum or rose anthracnose is becoming very important as a rose disease in Europe. Little information is found on this disease, partly because people think it is black spot. It appears often earlier in the season than black spot, the spots are mostly smaller than those of black spot and in the middle a grey area is formed which tends to form a shot-hole.
I just wonder if it is also present in other parts of the world. So, it would be nice if you could take a look at the picture on the link below and find out if you’ve seen this disease before.
Best regards,
leen.
Link: www.sactorose.org/ipm/83anthracnose.htm
Its rare on roses here in Oregon (NW USA). However, it is very common on other plants here such as photinia, cornus or prunus (many more but those popped up in my head). That said, it has never bothered me much like blackspot does.
Baldo’s page is based on his experiences in California.
I’m on the other side of North America in far more humid conditions with a major river about a tenth of a mile from my roses in two directions.
Here, Anthracnose is more common in fall and follows Blackspot problems. In my garden it is a problem of Hybrid Perpetuals and Hybrid Teas predominantly and seldom bothers teas, noisettes, chinas and multiflora and wichuriana close hybrids,
The difference here is that Anthracnose leaves don’t drop but Black Spotted leaves do. Sometimes leaves will have both problems, but more often there is an offset in times of fungal activity. Anthracnose leaves can overwinter on the stems before dropping.
Here, too, the diseases are confused or more properly, the differences are ignored.
Here, we have Anthracnose as a major pestilence of Dogwood, (Cornus spp.), especially on Dogwoods in woods and the local ag. school has a plant pathologist working on the disease so we are more aware of it because of Dr. Mark Windham’s activity (as well as his love of roses.)
Locally our most effective sprays for anthracnose seem to be Mancozeb/Manzate followed by Daconil Ultrex and Cleary’s.
BannerMaxx was ineffective when used alone in my garden.
The other thing to do is to remove leaves when a single bush is the major problem in a garden, this has helped in my garden.
I find it frustrating when someone says that they sprayed and “blackspot” went away when often the spray has nothing to do with it…it’s just a change in temperature that suppressed the fungal activity.
Ann
We have it in the Twin Cities too. At the MN landscape arboretum it is especially a problem on the non-rugosa Explorer series. In past RHA newsletters I surveyed how much disease was on the roses in this garden and scored for black spot, anthracnose, and powdery mildew. This garden is typically not sprayed. I think that over the years anthracnose has built up there and is more problematic than in typical home gardens.
David
Like for Ann anthracnose follows blackspot here french Riviera with cooler late autumn temps. Smaller more numerous spots on leaves that do not fall or yellow but stay as long as if healthy. Quite debilitating although.
Without any sprays a var may be resistant to blackspot and anthracnose ridden one month later.
Such is Frederic Mistral aka The Children’s Rose here…
Has this behaviour been observed and on other vars?