January 2005. Vanuatu asked if there are any new products for the control of nut grass. Glyphosate is effective, but it is expensive.
The following suggestins were received:
1. Depending on your crop, both chickens and geese give excellent control of this perennial sedge. At Palau Community College, chickens vare used very successfully, fenced in with taro – they will not eat the taro. However, chickens will defoliate young cassava. Geese and chickens can be grazed under bananas and other crops, separately or together. Chinese cabbage would not survive under this treatment!
2. Manage or SedgeHammer Turf Herbicide (halosulfuron-methyl) is a selective herbicide used for the control of nutsedge (Purple Nutsedge, Yellow Nutsedge) and other weeds in turf grass and landscaped areas. Use Manage herbicide for post-emergent control of sedges in established lawns, ornamental turfgrass and landscaped areas. May be applied to commercial and residential turf and on other non-crop sites including: airports, cemeteries, fallow areas, golf courses, landscaped areas, public recreation areas, residential property, roadsides, school grounds, sod or turf seed farms, sports fields, landscaped areas with established woody ornamental and other similar sites.
3. In Northern Australia SEMPRA[R] is used in sugarcane, corn, maize and sorghum (this is another product for alosulfuron-methyl). In a cropping situation, good results have also been obtained with Amitrole [Amitrole T[R] or Illico[R] as a directerd spray to the nutgrass . It generally does not damage the crop if used correctly, but a test should be done first. In a turf or pasture situation, 2,4-D amine has given good results. It kills off the top nuts and does not affect the grass and is cheap. Any herbicide treatment must be combined with deep cultivation [deep ripping is usually adequate] to get long term control. Kill the top and shallow nuts with herbicide, deep rip to stimulate the deep nuts to germinate, kill the regrowth and keep on doing this until no more come up.
Images of nut grass can be found at http://images.google.com/images?q=cyperus+rotundus/. Information is availbe on the CABI Crop protection Compendium.