Joyce,
Where did you say you got your mosquito granules from? I want to mix some in my soil per your receipe for the BT so I don't have to bother spraying the water lily pads. I have mosquito dunks floating in the water, but still get some caterpillars, so maybe it floating in the water is not getting into the plant systemically. I found the dunks at Lowes and Home Depot, but have not seen it in granular form anywhere.