Garden weirdness, Part I

Fungus
Originally uploaded by croatoan_found.

I've been noticing some very odd looking maple leaves in my yard. I was going to stop by a local nursery to ask what's up when an article in the Boston Globe provided an answer: Fungus.

Arborists say the biggest problem they are seeing is anthracnose, a fungus that causes the veins of a leaf to turn brown before overtaking its edges and then the entire surface. The disease usually starts in the lower branches of trees and spreads upward, causing many leaves to crumple and drop as it spreads.

The second fungus, called ``tar spot," mostly affects Norway maples -- trees common in backyards and along city streets. The fungus infects the leaves in the spring, but few people notice until late summer, when the fungus reproduces and spreads. Most leaves afflicted by this fungus don't drop, although in severe cases the tar spots can defoliate trees, said Bob Childs, an entomologist at the University of Massachusetts Extension in Amherst.

Like the mosquitoes, ticks, and caterpillars that found the wet spring favorable for a population explosion, the fungi thrived in the dank soil. Winds then blew millions of spores onto trees, and the fungi began growing. The fungi will drop from the trees when the leaves do, then lie dormant on the ground during the winter until the right conditions awaken them again.

Maples appear to be the hardest hit this year, but other types of fungi are affecting other trees.

The remedy? Rake all the leaves (duh!) and apply a fungicide next season.