What's the liquid? We use bologna pieces for wasp traps. A liter bottle? Have you caught wasps in it?The weather is supposed to turn cooler here after the tropical storm moves through. I'm going to hold out for then and then clean the coop. Hopefully my back will be on friendlier terms with me by next week. Then I need to Ivermectin the birds when I clean.
For flies I use a liquid bait that you put in a pop bottle type trap. The stuff smells like rotted meat. Really nasty but the flies are drawn to it, get down in the pop bottle and can't get out. I've had over a liter of flies in less than a week. Pretty amazing really.