Tar spots on maple leaves

Today's blog is a reprint of a post that first appeared on Rockinon: the blog. Lately, I've been noticing these tar spots on fallen maple leaves in London and so I thought a reprint was in order.

A lot of the information came directly from a report from Guelph University by W.A. Attwater. I think it is best to ensure accuracy and so I am leaving this report essentially untouched.

Whenever I saw round, black dots on maple leaves, I used to wonder what the black dots were and what measures should we be taking to protect our trees. If you have thought the same thing, read on.

These distinctive round to irregular black, spots on infected maple leaves are known as tar spots. Not noticeable until late summer, tar  spots are caused by two species of Rhytisma fungus.

The first, Rhytisma acerinum, produces black, tar-like spots about 1.25 cm or more in diameter on the upper surface of infected leaves. The second species, R. punctatum, produces patches of small, 1mm wide spots and is often called speckled tar spot.

The thickened black spots are fungal tissue called stroma. Red, silver, Norway (including the varieties with red leaves) sugar and Manitoba maples as well as others are affected.

Both fungi survive between seasons on the fallen diseased leaves. In the spring, spores are produced within the black stroma and are carried by air currents to young maple leaves where they start new infections. Unlike many other foliar diseases, Rhytisma spp. do not continue to cause new infections throughout the summer.

Infections first show up as yellow or pale green spots on the leaf surface in the early spring or summer. The black, raised tar-like spots develop within these spots in mid to late summer. Severely infected leaves may be shed.

Although tar spots are conspicuous, they are seldom so injurious in home gardens to justify spraying with a fungicide. As the strong visual appearance develops late in the growing season, the overall health of trees is rarely affected.

To reduce the amount of disease overwintering, rake up fallen leaves in the autumn and destroy or remove them from the yard.

Walk in the bog

The boardwalk running through the wettest part of the Sifton bog protects the bog while allowing folk to walk deep into the woods to view the central pond.

This would make a great picture if taken at time when the early morning mist was thick.

Is pot as harmless as most of us think?

"Is pot really harmless?" This is the question posed by Dr. Elizabeth Osuch. For her answer check out my linked post: Pot.


Today's picture was taken of Osuch as she delivered her lecture in Wolf Hall in the London Central Library.

More Photos from the Strength Behind the Uniform Walk/Run

There was a request for more photos from the weekend charity walk/run. For more info click the Strength Behind the Uniform Walk/Run link.

This was the second year for this charity event. The walk/run attracted more participants this year than last. Maybe this event will become an annual opportunity for the community to show support for our troops.

Strength Behind the Uniform Walk/Run

Sunday morning hundreds of Londoners turned out to participate in the Strength Behind the Uniform charity walk/run honouring the Canadian military and giving support to their families. The 5km/8km walk/run was hosted by the London Military Family Resource Centre (LMFRC) with the aim of raising community awareness of the number of military families living in London and to gather funds to support local LMFRC programs and services.

Yellow ribbons marked the route through Springbank Park but one could just as easily have followed the yellow T-shirts worn by many of the participants. The yellow ribbon is the support-our-troops symbol adorning the backs of many Canadians cars

This is the second year the LMFRC has held Strength Behind the Uniform and this year's event proved to be even bigger and better than the first.

A ceremonial start was provided by the London Police Pipe and Drum band. Earlier, one member of the band was spotted warming up, marching and playing his bagpipe in a distant parking lot at the large park.

Shannon Kisslinger, Chair of the LMFRC board of directors, told The Londoner, a weekly tab carried by The London Free Press, "This event is important to promote awareness of the military families in the London region. There is a particular focus this year on the families who are combating stress while their loved ones are deployed. Even joyful times, from weddings and baptisms to graduations and birthdays, can be stressful both for the soldier who is unable to be there and the family who feel their loved one's absence even more acutely on those special occasions."

Kisslinger continued, "Aside from deployments, family separation is common for some military families as Canadian Forces personnel are required to be away for overseas and domestic operations and for training. The military lifestyle is certainly unique and we work to enhance the quality of life for all military families living in our catchment area, across Southwestern Ontario."

While participants had the choice of  either a 5 km or 8 km route, there was an third option taken by some, especially those with young children on the course. Do a little walking or running and then take the kids to the reptile tent or allow the kids have their faces painted or involve them in some of the family games.

For more photos, please click here. This was done for you, Matt.

A walk in the woods

I had heard that there was a walk scheduled for the Sifton Bog Saturday morning. I went but found no one. Maybe I was a little late; I don't know. (Now, I believe I was early --- a day early. I think there is a walk at the Oxford West bog tomorrow, Sunday, Oct. 25th.)

Oh well, I still got a picture when these wild flowers, purple asters, caught my eye.

Holy Roller

The Holy Roller is a Second World War Sherman tank sitting in the northern end of Victoria Park in central London, Ontario. It sits as an everlasting memorial to the soldiers of the 1st Hussars who, together with other Canadian and allied servicemen, liberated The Netherlands. A plaque notes that many lost their lives liberating France, Belgium and Holland following the allied invasion of Normandy on D-Day, June 6, 1944.

For a trivia quiz on the tank, click here.