Fleabane has become one of the most difficult-to-control weeds in dryland cropping systems in recent years, The weed problem is thought to have resulted from recent changes in farming practices toward greater use of zero tillage, and possibly from recent seasonal conditions that have favoured fleabane growth. Some preliminary studies on fleabane biology indicated that the seed emerged only on or near the soil surface, and that seed persistence was relatively short. The weed seemed to emerge throughout the year, but peak emergence was during spring, particularly under wet conditions. One mature plant can produce an average of 11 0,000 seeds.