Clopyralid for knockdown and residual control of flaxleaf fleabane in broadacre cropping and fallows

摘要

Flaxleaf fleabane (Cony:a bonariensis (L.) Cronquist) is a weed of national significance in cereal crops, fallow land, roadsides and non-crop situations that is now found in every state of Australia. There are seven species of Conyza in Australia, butflaxleaf fleabane is most widespread and prevalent in broadacre cropping systems. Flaxleaf fleabane is hard to control due to the timing of emergence, rapid growth habit, limited herbicide options, increased tolerance to herbicides with maturity and large seedset (100,000 seeds per plant average). Uncontrolled flaxleaf fleabane seedset in any of these situations results in widespread dispersal as seed is moved readily in wind.The aims of this work were to determine the rate of clopyralid (Lontrel~(TM) Advanced Herbicide) to control seedling flaxleaf fleabane in crop and the length of residual control provided during the fallow phase.Results have shown clopyralid applied in cereals provides excellent control of flaxleaf fleabane seedlings and residual control of new germinations.