Hello Every one. What your talking about sounds like what we are fighting here in the Pacific Northwest. We call it shotgun spores. Starts out looking like some one took a pen and started tapping on the wood or siding, little black dots.

We have found that this is just another specie of mildew spore. Out here if you don't get them under controll, the little black dots will grow into big black dots and pretty soon they will take over the whole house and turn it black.

Mildew spores are every where. They are air born and will settle on anything, encluding a freshly cleaned deck or house. The more trees and shrubery you have around the house, the more spores you have air born. Once they are on the house or deck, conditions have to be just right and then they start to grow into the black dots. In other words, the black dots are the spores growing. It's like a carrot, you can't see the carrot in the ground, just the bush above.

We have found that by using a commercial mildewcide, we can controll and stop their grouth. Bleach may retard their grouth but it won't stop them from coming back.The product we use will.

Mildew spores can remain dormant for years. Conditions have to be just right before they start to grow.

Hope this has helped a little.

Jim Bilyeu
Exterior Woodcare.

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