I'm looking for suggestions.... We have a major ant problem on our property (we have a large oak tree), no ants in the house, but every year they fill our yard. We've been combating them with bait, Seven, Ortho Home Defense, and EcoSmart Ant killer but with little impact. I'm at my wits end. I'm about ready to call a company for help, but just in case does anyone have suggestions? If not, have you used a company that you recommend? Thanks!