The left wing of the aircraft struck a powerline from below during a pull up from a clean-up run. The aircraft rolled along its longitudinal axis and struck the ground inverted in an adjacent paddock. The cabin of the aircraft remained intact, consequently the pilot was not injured. The clean-up spray run was flown at about 90 degrees to the previous spray runs and parallel to a high tension power line running north-south. Immediately south of the paddock the power line converged at about 20 degrees and joined a power line at approximately 80 degrees to the high tension line. The pilot said that the converging wire had not been an obstruction for his spray runs as the convergence started outside the field. He said that he saw the converging power line too late to avoid it.