Question: My plants’ leaves have almost perfect circles cut into their edges. What kind of insect does that? I can’t find any insects on the plants, yet the damage keeps getting worse.
Work of leaf-cutter bee in floral bracts of bougainvillea
That’s an insect called a leaf-cutter bee. The female cuts those thumbnail-sized partial circles into the margins of the leaves, then carries them to an unused faucet or downspout and makes her nest. She doesn’t feed on the leaf tissues, nor is she there very long at a time. For those reasons, chemical controls are completely out of the question. Any damage they do is minimal. Just learn to enjoy the unusual insect and its lifestyle. Any greater concern will merely frustrate you. The damage, by the way, will probably be less in other years.