November 2011

 

Progress update

• We have discovered that mowing Californian thistle (Cirsium arvense) during rainfall improves the level
  of control by 30% on average, and recommend this technique to pastoral
  farmers throughout NZ. See a video created by members of the Undermining Weeds science team.
  
  
• The biocontrol agent Cleopus japonicas is causing widespread damage to the forest plantation weed Buddleja davidii in the central North Island. This agrees with predictions from our population dynamics model. Further research will provide foresters with guidance on where further releases of C. japonicus are likely to be most effective.
  
  
• Our work on process-driven models for spray droplet bounce, adhesion
  and shatter has gained international recognition as one of the most
  interesting analyses of the problem of spray retention and an extremely
  promising model. Further development of these models will make it possible to tailor spray formulations, as well as application technologies, to maximise retention to plant foliage and minimise loss to the environment.
  
  
• Our climate-based model of the potential distribution of Chilean needle
  grass across New Zealand’s productive grasslands has been used to categorise this weed as a “Containment” species on the Canterbury Regional Council’s Regional Pest Management Strategy. This classification provides the legal basis for the CRC to take actions necessary to prevent the weed spreading from the 80ha of infested pasture at its only known site of occupation (in North Canterbury), to the 1.2 million ha that are climatically suitable throughout eastern Canterbury.

In the following pages we give more indepth details of a further three projects undertaken within the programme under the general theme “integrated weed management”.