By PAUL HETZLER

Ah, the colors of fall: the mottled olive greens, subdued sepias and shades of brown. If you’re seeing those colors this late summer or early fall, it could lead you to become clinically depressed, considering what follows. It’s more likely, though, that the leaves themselves are depressed; you see they had a terrible spring.

The period of March through May 2011 was the wettest on record, (water) logging in 56 days of measurable precipitation totaling around 220 percent of normal. Fungi flourished under those conditions, setting up housekeeping on and in foliage of all sorts. While infections occur in April and May, most symptoms don’t start showing up until summer.

Maples were particularly hard-hit this year with something called anthracnose, although ash and oak have also suffered. Anthracnose manifests as brownish discoloration along leaf veins followed by large irregular brown patches throughout the leaf. It causes early leaf drop as well as a condition called “ugliness” but is rarely a threat to the health of the tree. Later on, maple leaves began sporting round, dark splotches resembling tar spots. In a rare oversight, the scientific community has dubbed this disease Tar Spot instead of something like “Rhytismapunctitis.” Tar Spot is not a cause for concern.

Apples, crabapples, mountain ash and their close kin have suffered the defoliation, not to mention the social stigma, of scab. Scab loves a wet season, and the best way to beat it is to keep the trees pruned and provide 100% full sun or else plant resistant varieties. Powdery mildew has had a great year on lilacs, roses and anything else it could get its grubby mycelium-mitts on.

Evergreens are not exempt from fungal pathogens and while they do shed needles annually, some trees are looking more brown (or sparse) than they should. Incidentally, the greenish-gray lichens (“moss”) on trunks and branches are simply looking for a parking spot where they can photosynthesize and are entirely harmless. They become more abundant as a tree declines because there’s better sun.

So long as precipitation next spring is close to normal, affected trees should be fine next year. You can minimize the chance of reinfection by raking up and disposing of all infected leaves, and by pruning and destroying dead branches. Should you feel compelled to chemically treat for any of these conditions, be aware that the time to do so is in the spring before symptoms appear.

For further information contact Cooperative Extension at ph59@cornell.edu or call 379-9192.

Things should brighten up as we get deeper into fall—keep your glasses clean and lichen-free so you don’t miss it.

Paul Hetzler is a forester and a horticulture and natural resources educator for Cornell Cooperative Extension of St. Lawrence County.