Question

My tree   I have an Indian Bean Tree on which the leaves turn black in the fall instead of the Normal fall colors.  I am not sure if it is a disease or a soil problem.  Any information is appreciated.  Linda

Answer
Hi Linda:

I am not aware of any catalpa diseases in which the leaves turn black.  There is a situation called "sooty mold" in which the leaves will blacken.  This happens as a result of an insect infestation from insects like aphids, scales, or white flies. To determine if this is sooty mold on your tree, use a wet paper towel and wipe some of these black leaves.  If the black rubs off onto the paper towel, then this is probably sooty mold. Using Google, take a look at this problem on other plants such as gardenia or crapemyrtle.  Sooty mold is a fungus that grows on the excretement of the insect.  You can also collect a few of these leaves and carry them by your local garden center for their opinion.

Regards
Steve