Special Weeds in Cropped Areas – Nut Grass or Nut Sedge
A few special weeds observed in crop plants are associated with crops. They create difficult problem to control because they produce innumerate seeds and their underground parts such as rhizomes, stolons and root stocks, bulbs and bulblets and tubers, which are beyond the reach of the routine cultivational practices.
Nut Grass or Nut stages:
It is perennial herb reproducing by seeds (nuts), rhizomes and tubers. Species in India are C.rotundus (purple nut sedge) and Cyperus esculentus (yellow nut sedge) the tubers maybe found as deep as 60 cm in soil.
Infested are sugarcane, cotton, wheat and almost all crops.
Hand weeding is most effective. Summer ploughing exposes and dessicates the tubers. Intensive cultivation is recommended. Ploughing and discine separate stolons. Spray 2.4-D on those germinating @ 1 kg/ha in 550 lit. water. Repeat the same as flushes come. Use Simazine @ 2 kg/ha in Simazine resistant crop as pre – emergence application. TCA, Methyl bromide and Sodium chlorate are also followed by harrowing, discing effectively. Pre – emergence spray of MCPA and 2.4-D delay germination of tubers. In soybean, use Lasso and Nitrogen as pre emergence. Jowar for fodder, soyabean, Mung, Sunbemp Sweet potato, Dolichas lablab are the smother to suppress the weed.
In rainy season continue the tillage so as starve the nut sedge from reserved food. This tillage should be performed shallow and every time when nu sedge shoots are 13-20 days old.
2.4-D, Amitrol, Liquid atrazine, Paraquat, Propanil Linuron etc.