Abstract
Narrow-leaved ragwort (Senecio inaequidens) is an invasive alien species and a poisonous weed containing pyrrolizidine alkaloids (PA). It usually spreads in rural environments along communication ways such as railroads and road embankments, but it can occasionally thrive also in dry grassland. As PA cause irreversible liver damage to animals and can also be retrieved in the milk of dairy animals, a control of this weed is advisable to ensure an adequate forage quality. In order to deene viable control strategies, the eeect of mowing or hand-pulling, carried out at four diierent phenological stages (before owering, at owering, at seed ripening and at the end of the growing season), was investigated in a four-year eld experiment in a mountain environment in the Venosta Valley (South Tyrol, Italy). Once a year the density of weed plants, subdivided into four diierent size classes, was assessed before the earliest treatment. Hand-pulling rapidly decreased the proportion of medium-sized and large-sized plants, while mowing did not apparently change the proportion between size classes. Hand-pulling was twice as eeective as mowing, and the highest eeectiveness was achieved if the treatment was applied towards the end of the growing season.