Question
Hi Kathy,

I reside in the Bahamas, the Key Limes use to thrive in the Bahamas for the past 12-15 years has drasticaly declined. My lime trees has a black gum on the leaf and trunk no matter how I try to treat it, there is no help, It is throughout the Bahamas, any help assisatnce you can provide will be greatly appreciated.

Thanks,
Tony

Answer
Hi Anthony, It is called sooty mold caused by aphids.  It can be washed off with soapy dish water or use and insecticidal spray for longer lasting results.  I must be getting poor air circulation or maybe overhead watering and the plant not drying out fast enough.  kathy