I bought a lemon and a lime tree last year. The Tropical Nursery advised that I plant Nasturtiums around them to prevent aphids. Apparently the insects would rather eat the juicy flowers than bother to climb up the tree. Something has almost destroyed the Nasturtiums, or maybe they are just at the end of their growing period. I have now planted marigold seedlings. The leaves of the trees have been eaten up. And the unusually wet Durban has brought out snails by the million. What to do about them, what to do?