mold inhibitors?

[dnf777]

I trailer my Precision 15, and keep it outside by the barn, under a well-vented canvas cover. Each time I pull the cover off, there is a black "dirt" all over the textured fiberglass decking. It powerwashes off easy enough, but I'm beginning to think it is a mold or mildew rather than dirt, since dirt really has no way to get under the cover. And its always ****-n-span clean before covered.

I keep a good marine wax on its surfaces. Does this sound like a mold/mildew problem? Is a good marine wax and frequent washing the best course? Is there a good wax/inhibitor I should be using?

Thanks in advance....I hope I gave enough info for some answers.

(I'm in western Pa, where its' been a warm, humid summer--not by Florida standards, but probably enough for mold growth!)

[RichH]

Probably 'artillery fungus' (sometimes called 'shotgun mold'), a fungus that thrives on tree bark and usually shows up after long periods of humid weather on 'most' exterior surfaces, especially in spring. Look at the roof on your house, barn, etc. its probably there too. You cant stop the spores from drifting on the wind; but, I've found that putting a few bare (non anodized) scraps of aluminum sheeting seems to keep it in check .... on roofs, etc.
You can also lightly 'mist' surfaces with caustics such as detergents containing sodium silicate - a modern 'equivalent' to old fashioned 'whitewashing' - but such will quickly destroy any applied 'wax'.