Sycamore tar spot, where is it?

[daltontrees]

It certainly isn't up here in Glasgow. I started to notice a month ago that there wasn't the usual ubiquitous peppering on sycamores, but now I am positively astonished at how little tar spot ther is this year. The leaves are just starting to fall and regularly I can find trees with no spotted leaves.

Is it the same in other parts of the country. And why or why not? Wettest summer in 100 years? Warmest march? Coolest 2nd quarter?

[sloth]

Rhytissma? Seen plenty in Essex...

[Joe Loggs]

Rhytissma? Seen plenty in Essex...

 

Yup seen lots in Essex.

[skyhuck]

My understanding is that the black spots on the leaves are just where the aphid eggs were attached to the back of the leaf and have no affect on the health of the tree.

 

I guess with the weather this year there will have been less aphids and so less spots.

[Graham]

The black spots are the fungal infection. Nothing to do with aphids.

[David Humphries]

Prevalent in London & Suffolk this year.

 

 

Rhystima acerinum

 

 

.

[skyhuck]

The black spots are the fungal infection. Nothing to do with aphids.

 

Next year I'm going to draw (with a maker pen) round some of the egg clusters on the back of the leaves on some of our sycamores and see if that area goes black come autumn.

 

I'm sure there is some correlation between the eggs and the spots.

[arbwork]

and here in Milton Keynes

[daltontrees]

I remember reading somewher that R. acerinum overwinters as spores in leaf litter and reinfects the tree every year but I don't know what the vector is. I'll look into it and post anything I find. Who knows, aphids could carry the spores but if they overwinter in bark or on stems it's not so likely that they are the vector.

Anyway, that's odd that you are getting plenty of tar spot down south but we aren't up here. It's a much needed boost for the sycamores not to have their photosynthesising capacity reduced, it has been a dull summer with only a handful of sunny days that I can remember.

[daltontrees]

Sorry, David, I just found where I read about overwintering...