Paraquat for taro

TaroTaro is a tropical starchy root crop which is a staple food in many subsistence communities, particularly in the Pacific islands. Often called “the potato of the tropics” taro makes up almost 20% of peoples’ daily calorific intake in some areas, compared to only 3-5% represented by potatoes for people in the US and Europe. Economically, it is an important source of export revenue, mainly to supply ex-patriot islanders living in Australia, New Zealand and the west coast of the US. As a tropical crop, protecting taro from weeds is essential. Weeds thrive in such hot and humid climates, robbing yield. 
“Paraquat in Samoa is not only helping farmers to provide a staple food but is also enabling taro to become a very important export crop as well. It is the only product I know of that can be used with safety to the crop."
- David Browne, Venture Exports New Zealand. David has over 30 years of experience in the Pacific Islands.
Dryland taro is more common than the alternative flooded cropping system, reaching harvest faster, but with lower yields. In this system, taro must be planted at the start of the rainy season. Weed control is critical in dryland taro, particularly in the first 3 months. Weeds thrive in such climates and a huge range of annual and perennial species have to be controlled by hand-hoeing or by spraying herbicides. 

Taro fact file

  • 1.3 million hectares grown worldwide
  • 80% grown in Africa, especially Nigeria
  • 5 to 15 months from planting to harvest
  • 20% of daily calories may come from taro
Paraquat is the preferred herbicide for controlling seedbed weeds because of the broad spectrum of control and because the risks of leaching


The natural process by which water soluble substances are carried downward through the soil into groundwater.
and crop damage from other products are often too great. As paraquat is deactivated immediately on contact with soil, and because small quantities of spray hitting crop leaves cause only localised, temporary, damage, it may be used confidently after planting up to when the crop starts to emerge. Close to emergence, the risk of damage from systemic non-selective


A chemical product used for eliminating all types of weeds (annual and perennial grasses and broadleaved weeds).

Authoritative On-line References and Resources An invaluable source of contemporary information about herbicides and weeds from Iowa State University.
herbicides like glyphosate contacting emerging shoots is too great. 
If hand tools are used for weeding the crop, care must be taken to avoid damaging the shallow roots and developing corms. Glyphosate cannot be used for spraying between rows because of inevitable contact with the crop. Glyphosate quickly moves from the point of contact throughout plants and small quantities can cause extensive damage. Oxyfluorfen is a herbicide with soil residual and contact Taro growing in Samoaactivity which can be used post-emergence if the spray is carefully directed between crop rows. However, there is some risk of damage as oxyfluorfen is volatile. Paraquat, however, is widely used for inter-row weed control in taro. It cannot move through soil to damage roots; spray droplets hitting crop leaves will not damage yield; and it does not produce any vapor. Also important, especially for weed control in tropical rainy seasons, is that paraquat is rainfast within 15-30 minutes of application. As regular rain is essential to dryland taro production, rainfastness is a major advantage.