[troutman]

Originally Posted by undercoverbrother

I was cutting my grass yesterday and noticed a white substance on the blades of grass. Kind of a powder. Does anyone know what this might be or what causes it.

No it is not Cocaine.

http://www.ag.ndsu.edu/pubs/plantsci...cap/pp950w.htm

Powdery Mildew is a common problem on bluegrass lawns in shady areas. The mildew fungus, Erysiphe graminis, attacks the surface of the grass leaves, developing a fine, fungal growth that resembles a white powdery substance on the leaves (Figure 9). In dense shade, Powdery Mildew causes the affected areas of leaves to turn yellow, eventually resulting in the yellowing and dying of lower leaves or even in the death of plants.


Powdery Mildew develops in areas of dense shrubbery or trees where there is poor air circulation, considerable shade, and high humidity. It is favored by temperatures of 60-72 F. In many cases, Powdery Mildew can be controlled by selective pruning of shrubs to allow better air circulation and greater penetration of sunlight. Where Powdery Mildew is a problem, avoid susceptible grass varieties or plant alternate ground covers.