Question
my daughter has a mango tree, which recently sent up quite a few flower stems, which were covered with little buds. in the last two weeks it seems that all the buds have dropped off and the tip  part of the stems have turned grey and brittle.  some of the leaves have dark spots. can you offer some advice. thanking you in advance for your help.

Answer
Thelma:
I am assuming that this tree is not a new tree, but has been established in the soil for sometime. If that is the case, I do not suspect a disease or insect, but rather some environmental stress, such as a sudden drop in temperature/change in light or watering schedules.  Many things can cause these symptoms that you describe. It would be best to have someone who could actually see the tree. Consider contacting your local county Extension office (each county in each state has an office of some type) or you can visit with your local nursery or garden center for suggestions.  You may be able to carry them one of the twigs and have them look at a physical sample.

I hope this can help.  If you are in the US and need the number of your county Extension office, let me know your state and county and I can get you a telephone number to call.

Regards
Steve