Spray affected plants with a ready-to-use systemic insecticide that contains acephate, imidacloprid or dinotefuran. Systemic formulas do not kill bagworms directly. The active ingredient is absorbed into plant leaves and needles, and then circulated throughout the plant. The insects die when they feed on plant parts and plant sap.
Depending on the size of your garage, insulating the walls with batts of R-13 will typically run you about $400, the ceiling $600, and the garage door will cost about $600 if you do it right (See image to the left). You can use the pink Styrofoam stuff from Home Depot, but that will only insulate your door to about R-6.
The cost to install this type of insulation varies, depending on the home's location, the amount of labor necessary and ancillary supplies. A standard insulation project requires about 535 square feet of insulation, which averages $145 to $200.-values range from 11 to 38. The cost for batt and roll insulation starts at $0.12 to $0.16 per square foot for a three-and-a-half-inch barrier that provides a value of R-11.