Tony Miklos wrote:
Viruses, fungii and other nasty pathogens to trees are found on
leaves and these tree diseases will return year after year if you
don't remove the leaves in the fall.
Wow! It's a miracle there are such things as "forests". How did
they ever survive without people gathering the leaves?
You people are bone-heads.
Go and look at a natural, preserved forest area. Something at least 100
acres in size, and has been left in a natural state (no human activity)
for at least 80 years. You'll find at least a foot of organic loam on
the ground before you hit dirt / soil. You won't find a spec of grass.
In that foot of loam is a functioning ecosystem that you won't have in
your back yard. An ecosystem that deals with leaf-borne tree fungi in a
way that doesn't happen on your urban property.
If you want to imagine the natural state of a functioning ecosystem,
that's what you have to compare to. With no more than 10 feet
separation between trees.
And even in that situation, you'll find lots of trees in bad shape.
Lots of tree stumps and trees that have fallen over, lots of insect and
bird dammage to trunks, broken limbs opening up the heartwood to rot.
Bottom line is that sure, don't rake the leaves of your urban back-yard,
and your trees will get more black-spot and other diseases regularly.
It won't kill the tree, but the tree won't grow as fast or as evenly vs
removing those pathogens from it's environment by removing the leaves in
the fall.
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http://gerberink.hubpages.com/hub/Maple-Tree-Problems
Maple Tree Tar Spot
The fungus winters-over on leaves that have dropped to the ground. If
the leaves are not raked up in the fall, the spores will reappear in the
spring on the old leaves and spread to any nearby tree. Treating the
trees is usually not effective since the spores can travel from a
neighbor's tree onto your trees.
Anthracnose
Anthracnose is commonly mistaken for tar spot. However, the damage is
much more extensive as it affects not only the leaves but the branches
as well. The spots on the leaves are many, and are usually much smaller
than the 1/8 inch tar spots.
This condition commonly occurs when there are long periods of cold and
wet weather. The areas affected may include the dark small spots and
irregularly shaped dead and brown areas on leaves. The leaves usually
fall off in the early spring, followed by a second set of leaves which
will also die off. The branches may develop cankers which can girdle the
branches and kill them.
The disease is perpetuated because the fungal spores over-winter in dead
leaves. When there is a prolonged wet spring, the spores have a perfect
breeding ground. The spores are carried by the wind to other trees. Once
infected, the disease can over-winter in the host plant in the infected
branches and twigs.
The disease can be controlled by removing dead leaves in the fall from
the base of your trees. Fungicide can also be applied, but due to the
size and number of trees that may be affected, commercial applications
are usually required. You can call your local Cooperative Extension
office to find out what fungicides are legal in your state.
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See also:
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http://www.extension.umn.edu/distrib...re/dg6659.html
Horsechestnut/ Ohio buck-eye Aesculus spp.
- Leaf blight, Guignardia aesculi
- Rake up and destroy infected leaves.
Maple Acer spp.
- Anthracnose, Discula species and others
- Rake up and destroy or compost fallen leaves.
- Leaf spot, Phyllosticta minima
- Rake up and destroy fallen leaves.
- Tar spot, Rhytisma acerinum
- Infected leaves can be raked up and destroyed or composted.
Oak Quercus spp.
- Anthracnose, Apiognomonia quercinia
- Rake and destroy fallen leaves.
Poplar Populus spp.
- Shoot blight, Venturia tremulae on Populus sp. and hybrids; V.
populina on black cottonwood and balsam poplar
- Rake and remove leaves in the fall.
Walnut Juglans spp.
- Anthracnose, Gnomonia leptostyla (Marssoniella juglandis)
- Rake and destroy fallen leaves and nuts.
Willow Salix spp.
- Willow scab/Twig blight, Venturia saliciperda and
Glomerella miyabeana
- Rake and destroy fallen leaves and twigs prior to spring growth
Crabapple, Ornamental
- Frog-eye leaf spot, Botryosphaeria obtusa
- Rake up infected leaves.
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Any more wise cracks from you bone-heads?