spots on leaves

Question

What causes spots on leaves that turn red and yellow and drop off? Can these spots on leaves cause plant to die?

Answer 1

Can you be more specific on the plant you are having trouble with?

Answer 2

What plant are you referring to? It could possibly be a leaf blight, leaf spot or leaf scorch.

Here is an example illustrated with strawberries:
http://www.extension.umn.edu/garden/diagnose/plant/fruit/strawberry/leavesspots.html