The pilot reported that he was setting up to spray a corn field bordered by radio antennas. He had sprayed the field previously and planned to use the same pattern this time. However, on his initial pass, he focused on the inner guy wire anchor point, which caused him to inadvertently fly between the inner and outer guy wires. When he started to pull-up, the airplane struck the outer wire, separating 7 feet of the left wing from the airplane. The pilot was able to maintain control and ultimately returned to the departure airport. However, the airplane rolled to the left when he reduced power on landing and he lost control at that time. The pilot stated that there were no problems with the airplane prior to the accident; the engine and flight controls were performing normally before the impact with the guy wire.