Question
Dave, I have yellow curling leaves with black spot. Ive tried a fungicide also noticed very, very small red bugs. I treated with seven dust but nothing seems to work.  Also my zucchini has yellow leaves.  The squash get 4 to 5 inches and rot from the blossom down.  Also treated with seven dust. Would bone meal help with a calcium deficiency?  HELP!

Answer
The curling leaves with the black spots are most likely bacterial spot.  The fungicide will not help for this.  Try spraying with Hi-Yield brand Copper Fungicide.  It is perfectly safe and has a 0 day pre-harvest interval.  The copper will control the bacteria.  Repeat every 7-10 days if the problem appears to be moving up the plant and if you get rainfall in between sprays.  The red bugs are aphids.  Sevin dust should control them, but you are probably only putting the chemical on the upper leaf surface.  The aphids are on the lower leaf surface.  You may have to get a liquid sevin and make sure you spray on the undersides of leaves.  There is a 3 day waiting period to harvest fruit.  As far as the zucchini, try using calcium nitrate as a sidedress application.  About a tablespoon per plant about 3-4 inches from the base of the plant applied to the soil surface will usually help.  Also, do not let the soil water content go up and down.  Keep the soil evenly moist all the time.  Fluctuating water content will also cause the problem to be worse.  I hope this helps solve your problems.  Good Luck.