Purple nutsedge

Table I provides general information on the identified allelopathic weeds and the crops they affect. More detailed information on two of these weeds, johnsongrass and purple nutsedge, will be presented to show the tenuous nature of the evidence for allelopathy. These two species are undoubtedly allelopathic, at least under certain conditions. Rigorous proof that allelopathy is the agent responsible for even a specific portion of the interference exerted by them is not easily attained, however, even though these are the weeds with the best research data available of those weeds that occur in the Mid-South.

Purple nutsedge Cyperus rotundus L. cotton, peanuts soybeans, tobacco corn, cotton peanuts, sorghum soybeans, tobacco cotton (10) ... 

Purple nutsedge. Purple nutsedge, possibly the world s worst weed... 

In a replacement-series study, Elmore et al. (27) have shown that purple nutsedge is a stronger competitor than four other species, including cotton. The data are insufficient to document allelopathy, but nutsedge tuber residue has been shown to affect cotton seedling development (31). 

Table III. Yield of Radish (Raphanus sativus L.) Growing in Purple Nutsedge...

Acknowledgments. The cooperation of K. E. Frick in supplying Bactra for purple nutsedge control is appreciated. The helpful reviews of Drs. S. 0. Duke, L. G. Heatherly, G. W. Cathey, and G. 

Miles JE, Nishimoto RK, Kawabata O (1996) Diurnally alternating temperatures stimulate sprouting of purple nutsedge (Cyperus rotundus) tubers. Weed Sci 44 122-125 Miles JE, Kawabata O, Nishimoto RK (2002) Modeling purple nutsedge sprouting undersoil solarization. 

Patterson DT (1998) Suppression of purple nutsedge (Cyperus rotundus) with polyethylene film mulch. Weed Technol 12 275-280... 

Webster TM (2005) Patch expansion of purple nutsedge (Cyperus rotundus) and yellow nutsedge (Cyperus esculentus) with and without polyethylene mulch. Weed Sci 53 839-845 White GJ, Buczacki ST (1979) Observations on suppression on clubroot by artificial or natural heating of soil. Trans Br Mycol Soc 73 271-275... 

Peterson, J.K., Harrison, H.F. Sweet-potato allelopathic substance inhibits growth of purple nutsedge (Cyperus-rotundas). Weed Technol 1995 9 277-280. 

Sedges are similar to grasses except that they have triangular stems and three rows of leaves. They are often listed under grasses on the pesticide label. Most sedges are found in wet places, but principal pest species are found in fertile, well-drained soils. Yellow and purple nutsedge are perennial weed species which produce rhizomes and tubers. 

Clay K. New disease (Balansia cyperi) of purple nutsedge (Cyperus rotundus). Plant Dis 70 597-599, 1986a. 

S. Hashimoto, O. Kirino, K. Furuzawa, and H. Ohshio,). Pesticide Sci. Nippon Noyaku Gakkaishi), 8, 493 (1983). Specific Herbicidal Activity of N>(a,a-Dimethylbenzyl)butanamides against Purple Nutsedge. 

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