my cherry tree has white material all over it wont produce cherry ? what can I do
I'm not sure white the "white material" is without seeing it. Could you attach a good resolution photo clearly showing this material?
There is a couple of possibilities as to why it may not be producing fruit. If it is a young tree it might take up to 5 years before it is mature enough to produce fruit. Another possibility is that it lacks another pollinizer tree to pollinate it. Most cherry trees need two trees of a different, compatible variety blooming nearby at the same time to set fruit. If this is the case you will need to plant another cherry tree next to it that is compatible. See the link for Sweet Cherry Compatibility and Bloom Timing Chart at http://extension.oregonstate.edu/wasco/cultivars.
Another possibility is that the tree is an ornamental cherry, which does not fruit.