Tired of endlessly spraying for flies? Order your Fly Predators™ brand beneficial insects now so you can put them out before the weather turns warm again. Just after the last hard frost is optimum. If you start on time, you can prevent flies from ever starting to build up. Then by releasing additional Fly Predators on a monthly basis throughout the spring and summer months, you can keep the pest fly population suppressed to the point they're never any sort of nuisance.