Evaluation of the Relative Phytotoxicity of Herbicides to Cotton and Nutsedge

Weed Science ◽  
1972 ◽  
Vol 20 (1) ◽  
pp. 71-74 ◽  
Author(s):  
P. E. Keeley ◽  
C. H. Carter ◽  
J. H. Miller

The following herbicides were evaluated for relative phytotoxicity to cotton(Gossypium hirsutumL. ‘Acala SJ-1′), purple nutsedge(Cyperus rotundusL.), and yellow nutsedge(Cyperus esculentusL.) under greenhouse conditions: 2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide (alachlor); 2-chloro-2′,6′-diethyl-N-(butoxymethyl)acetanilide (CP-53619); 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione (VCS-438); 4-chloro-5-(dimethylamino)-2-α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone (San-6706); 2-(α naphthoxy)-N,N-diethyl-propionamide (R-7465); andS-isopropyl 5-ethyl-2-methyl-piperidine-1-carbiothioate (R-12001). Herbicides were incorporated 6.35 cm deep, at rates of 1.12, 2.24, and 4.48 kg/ha, into a fine sandy loam prior to planting. All treatments except the low rate of alachlor and VCS-438 controlled yellow nutsedge for 8 weeks. R-7465 and R-12001 at 1.12 kg/ha and San-6706 at 2.24 kg/ha controlled purple nutsedge for 8 weeks. Alachlor and CP-53619 were somewhat less effective against purple nutsedge than yellow nutsedge, but their intermediate rates suppressed purple nutsedge for 4 weeks. Even the high rate of VCS-438 was ineffective against purple nutsedge. Cotton, in terms of fresh shoot weight, exhibited considerable tolerance to 1.12 and 2.24 kg/ha of VCS-438 and CP-53619 and 1.12 kg/ha of R-7465. Applications of 2.24 kg/ha of CP-53619 and 1.12 kg/ha of R-7465, however, suppressed the development of lateral roots of cotton. Other rates of these herbicides and all rates of alachlor, R-12001, and San-6706 moderately to severely injured cotton in most of the experiments.

Weed Science ◽  
1968 ◽  
Vol 16 (3) ◽  
pp. 339-340 ◽  
Author(s):  
W. S. Hardcastle ◽  
R. E. Wilkinson

Purple nutsedge (Cyperus rotundus L.) and yellow nutsedge (Cyperus esculentus L.) tubers were stored at 5 C in soil treated at 0, 2, 3, 4, 6, 8, or 10 lb/A 2,6-dichlorobenzontrile (dichlobenil) for 2, 4, 6, 8, 10, or 12 weeks. Respiration of dormant tubers differed with species, unaffected by period of storage or dichlobenil concentration. Sprouting of untreated tubers decreased from 90% after 2 weeks storage to 43% after 12 weeks. Yellow nutsedge sprout production was uniform in time; purple nutsedge sprouting progressed to an 8-week high. Increased concentrations of dichlobenil progressively inhibited sprouting.


Weed Science ◽  
1971 ◽  
Vol 19 (5) ◽  
pp. 601-606 ◽  
Author(s):  
P. E. Keeley ◽  
R. J. Thullen

Nonradioactive and14C-labeled arsenical herbicides were applied to foliage of purple nutsedge (Cyperus rotundusL.) and yellow nutsedge (Cyperus esculentusL.) grown under greenhouse and growth chamber conditions. Disodium methanearsonate (DSMA) controlled purple nutsedge better at 20 and 29 C than at 13 C. Monosodium methanearsonate (MSMA) was as effective in controlling this weed at 13 C as at 20 and 29 C. DSMA and MSMA provided 80% or greater control of yellow nutsedge grown at the three temperatures. When plants were treated with14C-DSMA and14C-MSMA, greater radioactivity was detected in yellow nutsedge than in purple nutsedge. The apparent differential herbicide penetration of purple and yellow nutsedge leaves is believed to have contributed substantially to the control of nutsedge observed in this study.


2012 ◽  
Vol 26 (2) ◽  
pp. 294-299 ◽  
Author(s):  
Travis W. Gannon ◽  
Fred H. Yelverton ◽  
Lane P. Tredway

Greenhouse experiments were conducted to evaluate the effect of selective herbicide placement on sedge shoot number, shoot weight, and root weight. Sulfentrazone, sulfosulfuron, and trifloxysulfuron were applied to soil only, foliage only, or soil plus foliage. Sulfentrazone provided greater yellow nutsedge and false green kyllinga growth reduction compared to purple nutsedge. Sulfosulfuron provided greater purple nutsedge and false green kyllinga growth reduction compared to yellow nutsedge; these species responded similarly to trifloxysulfuron. Soil and soil plus foliar applications provided the highest level of growth suppression, indicating herbicide–soil contact is required for optimum sedge control with these three herbicides. Future research should evaluate techniques that optimize herbicide–soil contact to improve herbicide efficacy.


Weed Science ◽  
2008 ◽  
Vol 56 (5) ◽  
pp. 735-742 ◽  
Author(s):  
Theodore M. Webster ◽  
Timothy L. Grey ◽  
Jerry W. Davis ◽  
A Stanley Culpepper

The phase-out of methyl bromide requires alternative nutsedge management options in vegetable systems. Options that target tuber production, the primary means of reproduction, will be most beneficial. A study was conducted to evaluate the response of purple nutsedge and yellow nutsedge foliar growth and tuber production to a range of glyphosate rates. Glyphosate was applied at six rates between 0.41 and 2.57 kg ae ha−1to 5-wk-old nutsedge plants with multiple shoots. The rate of glyphosate needed to reduce growth 50% (I50) was similar for purple nutsedge foliar growth (0.58 kg ha−1) and tuber biomass (0.55 kg ha−1). In contrast,I50for yellow nutsedge foliar growth was 0.73 kg ha−1, which was greater than theI50for tuber biomass (0.41 kg ha−1). First-order tubers, those directly attached to the initial tuber, had anI50of 0.70 and 0.44 kg ha−1of glyphosate for purple nutsedge and yellow nutsedge tuber biomass, respectively. For all higher-order tubers,I50values ranged from 0.29 to 0.60 and 0.14 to 0.30 kg ha−1of glyphosate for purple nutsedge and yellow nutsedge tuber biomass, respectively. Glyphosate at 0.74 kg ha−1prevented fourth-order purple nutsedge and third-order yellow nutsedge tuber production (terminal tubers for yellow nutsedge). Fifth- and sixth-order purple nutsedge tuber production was eliminated by the lowest tested rate of glyphosate (0.41 kg ha−1). Effective nutsedge management options will require consistent control between spring and autumn crops. Glyphosate is economical, poses no herbicide carryover issues to vegetables, and minimizes nutsedge tuber production; therefore, it is a suitable candidate to manage nutsedges.


Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 506-512 ◽  
Author(s):  
Michael J. Horak ◽  
Jodie S. Holt ◽  
Norman C. Ellstrand

Genetic diversity within and among populations of yellow nutsedge (Cyperus esculentusL. # CYPES) was analyzed to evaluate and quantify the genetic consequences of the reported predominance of asexually-produced tubers as colonizing agents. Ten populations were examined using starch gel electrophoresis for allozyme analysis. Four populations of purple nutsedge (Cyperus rotundusL. # CYPRO) were surveyed for comparison. Twelve loci were identified in yellow nutsedge among the eight enzyme systems examined; ten of these loci were found in purple nutsedge. Yellow nutsedge showed relatively low genetic diversity. Most of the genetic diversity occurred as differences among individuals within populations (Hs), compared to differences among populations (Dst) for the four variable loci identified in this species. Thus, most genetic distancesbetween its populations were small. Generally, only a few genotypes occurred within each population. Purple nutsedge was found to possess even lower within- and among-population gene and genotypic diversity. This study supports the view that tubers account for most of the establishment of new populations of both species.


Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 201-207 ◽  
Author(s):  
Jill Schroeder ◽  
Stephen H. Thomas ◽  
Leigh W. Murray

Greenhouse studies in 1995 and 1996 examined the response of yellow and purple nutsedge to inoculation with increasing densities of southern root-knot nematodes. Yellow and purple nutsedge root and shoot weight, numbers of leaves and tubers produced, and tuber weight were unaffected across 17 nematode inoculum densities that ranged from 0 to 20,000 eggs per 15-cm pot, four times the maximum nematode density recorded under field conditions in New Mexico. Hence, yellow and purple nutsedge do not exhibit a classic threshold response to root-knot nematodes. Moreover, the results suggest that the relationship between these nematodes and perennial nutsedges is an example of a positive biological interaction. The relationship between root-knot nematodes and purple nutsedge appears to be one of commensalism, because while the nematodes reproduced effectively, purple nutsedge reproduction was not related to final nematode populations. The relationship between yellow nutsedge and root-knot nematodes appears to be a mutually beneficial one, because yellow nutsedge tuber number and weight and root weight increased as final nematode populations increased. However, while both nutsedges were unaffected in the absence of the association, root-knot nematodes cannot survive without a host plant.


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