Question
Hi Kathy
I live in North Florida and have a Sambo lemon tree that was planted last year (about 31/2 ft tall) The leaves are turning black and I've noticed little white mites or something swarming around it. someone told me to spray it with horticultural oil. Any suggestions. It had two huge lemons on it last year when I bought it, but nothing so far this year.

Answer
Hi Eva, You have sooting mold and aphids on your lemon.  Yes the horticultural oil will work, however, it will smother good bugs as well.  Check out Atomic Grow which is organic, will make your tree healthy again, and will keep the fungus, bugs, leaf minors off your citrus as well as all your other plants.  kathy