Iowa exterminators say the warmer-than-normal winter is keeping them unusually busy. Derek Wetlaufer is the manager of a pest control firm in Cedar Rapids. Wetlaufer says that ant calls are quite popular, which is unusual for this time of year.Wetlaufer says controlling the farrow ant is not easy. The farrow ant is controlled by using bait, not the typical spray.Wetlaufer says the warmer temperatures make it easier for the bugs to hang around.