Answer: That's a tough one. They stick the leave to the roof of their underground cavern and feed off a fungus that grows on the leaves. It is difficult to poisoning them. Some gardening insecticides, when applied to their holes, will severely weaken the colony, but none to my knowledge are labeled for leaf cutter ant control.
There is a formulation of Amdro for leaf cutters (note: not the same as fire ant Amdro). This is certainly a low tox option, but it is sold in large (25 lb.?) bags for the forestry industry, and the one time I tried it I was not impressed.
Your County Extension Agent may be able to suggest some products which if applied diligently over time will help eliminate the leaf cutter colony. Their phone number is 210-930-3091.
Thanks for the question and good luck!
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