While we are consistently focusing on the fauna of our wildlands and woodlands across the Americas, it is always worth a reminder that if there was no flora(trees, shrubs, flowers,etc,,,,,,,there would be no animal life............The bottom up forces(weather/flora) are in a constant dance with the top down forces(Carnivores) and their prey(herbivores) forging the dynamic swirl of equilibrium that we call "nature",,,,,,,,,,,,,,,,,,,And for those of us who walk our neighborhoods after a day of work or hike, camp, bird watch, fish and hunt on the weekends, the visual sights of flora are in our visual "headlights" constantly..............Interesting article below on what happens to the leaves on our trees as Spring bloom matriculates into deep Summer.............Many of the "scars and afflictions" that deface the leaves on trees are as the author points out below,only "skin deep" and not life threatening to the future health of the tree..............A good educational primer on this topic below

https://shar.es/1vqa3n

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THURSDAY, AUGUST 27, 2015

Afflictions Of Late Summer

 Tree Leaves Only Skin Deep

by Paul Hetzler

2 Comments

Being an arborist, I’m of course very
 mindful of complexion. Things like 
bruises and blemishes catch my eye,
 in addition to scabs, cuts, and even those 
out-of-place whiskers that appear out of
 nowhere. It sounds like a description of
 my aging skin, but I’m talking about 
blotches, warts and cuts that accumulate
 on tree leaves over the summer.

I suppose if we had to stand outside day
 and night all season, our skin would 
develop issues too. Those who work o
r play much outdoors need to be
 concerned about skin spots that 
suddenly show up. With tree leaves,
 that’s not the case – even the ugliest
 “skin” condition is generally no cause
 for concern.

One of the more alarming leaf 
disorders is called tar spot, whose
 symptoms are black blobs that often
 show up in late summer or early fall.
 Tar spot affects Norway, silver, red
 and sugar maples, in order of 
severity. The spots, which really do 
look like drips of roofing tar, seem
 to appear overnight, and sometimes
 cover much of the leaf. While it may
 look like a serious affliction, it’s 
really just a cosmetic issue
 (meaning if you’re good with
 cosmetics you can probably make
 your tree look pretty again).

Unlike the tar sands of northern
 Alberta in Canada, though, tar 
spots can’t be processed into 
crude oil. As disappointing as
 that may be, at least tar spot is
 not a problem. Spots are caused
 by several different species of 
fungi in the genus Rhytisma, 
which I mention because some
 of you play Scrabble.

If your tree’s leaves have sprouted
 tiny spindle-shaped structures
 that make it appear that the leaves
 need a shave, don’t worry. These
 are tiny galls, formed when a 
minute arachnid called an 
eriophyid (go for a triple score 
on that word) mite laid an egg, 
along with a dose of a plant 
hormone which directed the leaf
 to grow a little home for her 
young one.

Depending on the species of mite,
 these galls can be green, yellow,
 red or pink. Some are squat and
 thick, resembling a wart, but they
 are all completely harmless. 
Good thing, too, because galls
 shield the mites from anything
 you could spray on them anyway.

Believe it or not, scabs are caused
 by a disease called scab. I think it
 was late on a Friday when scab 
and tar spot were named, probably
 by a new intern who was later 
reprimanded for “making sense.”

 It affects apple, crabapple, 
hawthorn, juneberry and other
 trees in the rose family. Scab 
causes affected leaves to drop 
early, and is much worse in wet 
seasons when it can defoliate a 
tree by mid-summer.

It’s a serious problem for
 orchardists because it causes
 scab-like blemishes on fruit in 
addition to weakening the tree, 
so they routinely spray fungicides
 beginning at bud break. 

Other ways of managing scab 
include proper pruning, 
increasing air flow and access 
to sun, and buying scab-resistant
 varieties.

High winds, especially early-
season
 events, can tatter leaves, a 
condition called “leaf tatter.” 
(Same intern, don’t you think?)
 Japanese beetles, caterpillars, 
sawflies and other insects chew
 on leaves over the summer, 
while leaf-cutter bees remove
 perfectly scribed circles. 

All in all, many trees look 
bedraggled by September.
 Should you be worried?

Here’s a secret: by late summer,
 trees don’t “need” their leaves 
any more. While this is true, it’s
 akin to saying you don’t need
 another five bucks at the end
 of the year. It would be nice,
 but it’s not going to change 
the big picture. A deciduous
 tree expends a huge amount 
of energy investing in new 
leaves each spring, and its 
leaves have to make enough
 sugar from sunlight to “repay”
 the tree, plus a little extra for 
rainy days. By early August, 
trees have recouped their
 investment along with a pile 
of interest.

Late-season disorders are
 superficial and no cause for
 concern. But if you’re 
embarrassed by your tree’s 
appearance come late summer,
 you can always try cosmetics.

Photo: Rhytisma acerinum 

fungus on a European 
sycamore maple. Courtesy
 Wikipedia userAnnabel.

Paul Hetzler

Paul Hetzler is the Horticulture and Natural
 Resources Educator at Cornell Cooperative
 Extension of St. Lawrence County.

You can reach Paul at the Cornell Cooperative
 Extension office in Canton at (315) 379-9192
.

- See more at: http://www.adirondackalmanack.com/2015/
08/afflictions-late-summer-tree-leaves-skin-
deep.html#sthash.zCBG4Hck.cf5iiGcT.dpuf