If you worry about the return of West Nile Virus with summer mosquitoes, or just hate the biting bug, there’s a control method that doesn’t involve any chemicals. Livestock producers who don’t want to put pesticides in animal watering tanks are trying fish — tiny minnows they hope will eat immature mosquitoes so they don’t reproduce in the water. Iowa State University entomologist Donald Lewis isn’t convinced, however.He says it sounds like “a simple solution to a complex problem,” but he says it looks a lot like wishful thinking. Lewis says “minnow” is a generic term that can refer to any small fish, or the young of many other kinds. Most minnows are herbivores — vegetarians — so he says they eat water plants and won’t be seeking out living food like mosquito larvae. Dr. Lewis says minnows won’t eat enough to fight the mosquito problem anyway: Mosquitoes won’t be a big enough part of a minnow’s diet to make much impact. There’s another alternative, he says, that’s already in use. Farmers stock bluegill and bass in farm ponds, and those aggressively eat bugs, including mosquitoes. Lewis says stock tanks generally are probably not a source of many mosquitoes since the water doesn’t stand undisturbed for long periods of time. A tiny tropical fish called Gambusia is nicknamed “mosquito fish” and has been stocked in waters from New Jersey to Nebraska for ten or twenty years to eat the larva of the mosquito after it hatches in water.