The private pilot was conducting a touch-and-go in a tailwheel equipped airplane with a direct crosswind component of 15 knots gusting up to 20 knots from the left side of the airplane. During landing, the crosswinds began pushing the airplane to the right side of the runway. While correcting back to centerline the pilot reported that a combination of over-correction and gusty crosswinds caused a loss of control. The airplane ground looped, departed the left side of the runway, and came to rest upright with the nose of the aircraft pointed approximately 180 degree from runway heading. Damage was sustained to the wing spar.