Talstar P (Talstar One) is not directly labeled for maggots for the common house fly, but it would help with the maggot control as it would cause the fly population to decrease rapidly. It should be mixed at 0.5 to 1.0 oz. per gallon of water and applied on the exterior of the home focusing around windows, doors, areas of direct sunlight and where you notice the flies congregating. Using a fly bait trap such as the Flies Be Gone Trap to draw the flies away from the home is also recommended.
First be sure to protect your biggest investment, your home. Put up a barrier using Termidor SC. Please see our article on Barrier Treatments. For the tree, you can inject Dominion 2L.