Answer: The ants are feeding on little beads of nectar exuded from the tree, or they're herding aphids. Check to make sure there are no aphids or other sucking insects on the undersides of leaves or on the stems of your tree. (Sucking insects leave behind a 'honeydew' excrement that's high enough in sugar to attract ants.) If there are no other insects, the ants are finding tidbits of a sugary compound manufactured by the tree. You can stop the ants by placing a paper or cardboard collar around the trunk of the tree and spreading or spraying a product called 'Tanglefoot'. Make the collar 3-4 inches wide, wrap it around the trunk and tie it on with string. Then coat the collar with the sticky Tanglefoot. Ants that crawl onto the collar will be hopelessly stuck. Replace the trap as needed - ants have no conscience and will happily step over the dead bodies of their cousins and march right up the trunk of the tree.
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