Researchers released insects in Michigan this year to see if they would help control spotted knapweed. The plant produces chemicals that deter the growth of other plants and crowds out native vegetation.
But Michigan beekeepers say the plant provides an important source of nectar and pollen to keep honeybees productive and healthy.
Western states and big honey producing states like Minnesota and Wisconsin have used bugs in the past to kill knapweed.
It's unclear why the method is drawing such opposition in Michigan and not elsewhere.