Biological Control of Northern Jointvetch (Aeschynomene virginica) in Rice (Oryza sativa) and Soybeans (Glycine max) — a Researcher's View

Weed Science ◽  
1986 ◽  
Vol 34 (S1) ◽  
pp. 17-23 ◽  
Author(s):  
Roy J. Smith

Weed control strategies for rice (Oryza sativaL.) and soybean [Glycine max(L.) Merr.] emphasize integration of cultural and chemical practices (16, 30, 31). Numerous herbicides are registered and used as preplant, preemergence, or post-emergence applications for control of weeds in rice and soybean (3, 16, 25). Although these herbicide treatments control most of the problem weeds in rice and soybean, most fail to control northern jointvetch [Aeschynomene virginica(L.) B.S.P. # AESVI] in either crop. The two most effective herbicides, 2,4,5-T [2-(2,4,5-trichlorophenoxy) acetic acid] and silvex [2-(2,4,5-trichlorophenoxy) propanoic acid], for control of northern jointvetch in rice have been under the U.S. Environmental Protection Agency's (EPA) Rebuttal Presumption Against Registration (RPAR) process which may ultimately cancel the use of both herbicides in rice (50). New, effective control strategies are needed for control of northern jointvetch in rice and soybean.

Weed Science ◽  
1987 ◽  
Vol 35 (1) ◽  
pp. 127-129 ◽  
Author(s):  
Khosro Khodayari ◽  
Roy J. Smith ◽  
Howard L. Black

Preplant incorporation of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] at 3.6 kg ai/ha, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] at 2.2 kg ai/ha, and tank mixtures of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} with either alachlor at 0.14 + 2.2 kg ai/ha or metolachlor at 0.14 + 1.1 kg ai/ha controlled >90% red rice (Oryza sativaL. # ORYSA) in soybeans [Glycine max(L.) Merr.]. Also, FMC-57020 [2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone] at 1.7 kg ai/ha applied preplant incorporated controlled > 80% of the red rice. DPX-Y6202 {2-[4-[(6-chloro-2-quinoxalinyl)oxy]-phenoxy]-propionic acid, ethyl ester} was the best and most consistent postemergence herbicide treatment for red rice control when applied once at 0.28 kg ai/ha or sequentially at 0.14 kg ai/ha each time. Haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy] phenoxy] propanoic acid} applied at 0.16 kg ai/ha followed by another application at 0.14 kg ai/ha gave excellent red rice control in 2 of 3 years. Soybeans were uninjured by the herbicide treatments and yield was higher from treated than untreated soybeans.


Weed Science ◽  
1976 ◽  
Vol 24 (4) ◽  
pp. 385-390 ◽  
Author(s):  
C. G. McWhorter ◽  
J. M. Anderson

The effectiveness of several preemergence and postemergence weed control systems for control of common cocklebur (Xanthium pensylvanicumWallr.) in soybeans [Glycine max(L.) Merr.] was determined in field research over a 3-yr period. Sequential applications of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] at 1.1 kg/ha applied preemergence, and dinoseb (2-sec-butyl-4,6-dinitrophenol) at 1.7 kg/ha, 2,4-DB [4-(2,4-dichlorophenoxy)butyric acid] at 0.2 kg/ha, or bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide] at 1.1 kg/ha applied postemergence, provided at least 90% control of common cocklebur and increased soybean yields. Use of single herbicide applications was less effective than sequential applications, but metribuzin applied preemergence was more effective in controlling common cocklebur and increasing soybean yields than single applications of any herbicide applied postemergence. Effective control of common cocklebur with sequential herbicide treatments increased soybean seed grades by reducing discounts caused by several grade lowering components including moisture content and foreign material in harvested seed. Use of all herbicide practices increased returns above specified costs, but greatest returns followed use of sequential treatments.


Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 679-685 ◽  
Author(s):  
Russell S. Moomaw ◽  
Alex R. Martin

Weed control in no-till soybeans [Glycine max(L.) Merr. ‘Wells’] planted into shredded corn (Zea maysL.) residue was evaluated at Concord, NE, over a 3-yr period. Herbicide factors evaluated were time of herbicide application for no-till soybeans, efficacy of glyphosate [N-(phosphonomethyl)glycine] relative to paraquat (1,1’-dimethyl-4,4’-bipyridinium ion) for control of emerged weeds, and the efficacy of alachlor [2-chloro-2’,6’-diethyl-N-(methoxymethyl)acetanilide], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), and pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] for residual weed control. Combination residual and contact herbicide treatments were applied either as a preplant surface application or preemergence after no-till-planted soybeans. Removal of existing weed growth was not consistently better with the preplant surface application compared to later removal after soybean planting. Paraquat and glyphosate gave nearly equal control of emerged weeds. Addition of 2,4-D [(2,4-dichlorophenoxy)acetic acid] with paraquat in the tank mix did not improve weed control. Use of narrow, ripple coulters on the no-till planter resulted in minimal disturbance of the preplant surface herbicide so that additional preemergence herbicide at planting was seldom beneficial.


1989 ◽  
Vol 3 (4) ◽  
pp. 621-626 ◽  
Author(s):  
David L. Regehr ◽  
Keith A. Janssen

Research in Kansas from 1983 to 1986 evaluated early preplant (30 to 45 days) and late preplant (10 to 14 days) herbicide treatments for weed control before ridge-till planting in a soybean and sorghum rotation. Control of fall panicum and common lambsquarters at planting time averaged at least 95% for all early preplant and 92% for late preplant treatments. Where no preplant treatment was used, heavy weed growth in spring delayed soil dry-down, which resulted in poor ridge-till planting conditions and reduced plant stands, and ultimately reduced sorghum grain yields by 24% and soybean yields by 12%. Horsenettle population declined significantly, and honeyvine milkweed population increased. Smooth groundcherry populations fluctuated from year to year with no overall change.


Weed Science ◽  
1989 ◽  
Vol 37 (3) ◽  
pp. 392-399 ◽  
Author(s):  
Douglas D. Buhler ◽  
Virginia L. Werling

In 1985, when weed densities were low (169 plants/m2in untreated control), imazaquin applied at 0.07 kg ai/ha early preplant controlled over 90% of all weeds before no-till planting of soybeans. In 1986 and 1987 when weed densities were higher (589 plants/m2in untreated control), addition of 1.1 kg ai/ha or more of metolachlor to imazaquin (0.07 kg/ha) before soybean planting controlled 95% or more of the grass weeds and 83% or more of the broadleaf weeds. Imazaquin plus metolachlor applied less than 1 day after soybean planting controlled less than 70% of the emerged weeds in 1986 and 1987; common lambsquarters was most tolerant. Early preplant treatments controlled more weeds throughout the growing season than treatments applied after planting. Splitting herbicide treatments among application times generally did not increase weed control compared to single applications. Early preplant applications resulted in higher soybean densities and taller soybeans 30 days after planting in 1986 and 1987 than treatments applied after planting. Soybean yields increased as weed control increased. Weed control and soybean yields were greater with early preplant treatments than paraquat plus alachlor plus metribuzin applied preemergence in 1986 and 1987. No carryover of imazaquin residue was detected through corn bioassay in the field.


Weed Science ◽  
1975 ◽  
Vol 23 (1) ◽  
pp. 36-39 ◽  
Author(s):  
R. J. Smith

Postemergence herbicide treatments that controlled tighthead sprangletop [Leptochloa panicoides(Presl) Hitchc.] and redstem (Ammannia auriculataWilld.), did not injure water-seeded rice (Oryza sativaL.), and substantially improved grain yields included: (a) a single application of propanil (3′,4′-dichloropropionanilide) at 4.5 kg/ha applied to weeds 8- to 10-cm tall; (b) two sequential treatments of propanil each at 3.4 kg/ha, with the first treatment applied to weeds 2- to 5-cm tall, and a second treatment applied 4 to 8 days later; (c) a tank mixture of propanil at 3.4 kg/ha and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] at 0.6 kg/ha, applied to weeds 8- to 10-cm tall; and (d) a tank mixture of propanil and molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate), each at 2.2 kg/ha, applied to weeds 8- to 10-cm tall. Treatments that controlled tighthead sprangletop or redstem unsatisfactorily or inconsistently and did not improve grain yields as much as more effective treatments included: preplant or postemergence treatments of molinate, or preplant treatments of nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether), fluorodifen (p-nitrophenylα,α,α-trifluoro-2-nitro-p-tolyl ether), CNP (2,4,6-trichlorophenyl-p-nitrophenyl ether), or He-314 (p-nitrophenyl-m-tolyl ether).


Weed Science ◽  
1986 ◽  
Vol 34 (4) ◽  
pp. 582-586 ◽  
Author(s):  
James L. Griffin ◽  
Thomas R. Harger

Red rice (Oryza sativaL. # ORYSA) control in soybeans [Glycine max(L.) Merr.] was 93% or more with shallow-incorporated alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] at 3.9 kg ai/ha, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] at 2.8 kg ai/ha, and trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine] at 1.7 kg ai/ha. Junglerice [Echinochloa colonum(L.) Link. # ECHCO] control was 80% with alachlor but 90% or more with metolachlor and trifluralin when applied at the same rates. Sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} at 560, fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl] oxy]phenoxy]propanoic acid} at 280, haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} at 140, and mefluidide {N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl] amino] phenyl] acetamide} plus bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4 (3H)-one 2,2-dioxide] at 140 plus 840 g ai/ha applied postemergence on two- to four-leaf red rice provided at least 87% control. Junglerice control with these treatments was 85% or more with the exception of fluazifop and mefluidide plus bentazon.


Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 105-110 ◽  
Author(s):  
William G. Johnson ◽  
Jeffrey S. Dilbeck ◽  
Michael S. DeFelice ◽  
J. Andrew Kendig

Field studies were conducted at three locations in 1993 and 1994 to evaluate weed control and crop response to metolachlor plus combinations of 0.5 × and 1 × label rates of imazaquin applied preplant and imazethapyr applied early postemergence or postemergence in no-till narrow-row soybean production. Giant foxtail, common ragweed, common cocklebur, and large crabgrass population reductions were greater with sequential preplant metolachlor plus imazaquin followed by early postemergence or postemergence imazethapyr than with preplant metolachlor plus imazaquin or early postemergence/postemergence imazethapyr alone. Ivyleaf morningglory was not effectively controlled by any herbicide program. Pennsylvania smartweed populations were reduced with all herbicide treatments. Soybean yields with treatments utilizing 0.5 × rates were usually equal to 1 × rates if imazethapyr was applied early postemergence or postemergence. Net income with reduced herbicide rates was equal to full-label rates and provided no greater risk to net income.


Weed Science ◽  
2019 ◽  
Vol 67 (1) ◽  
pp. 57-67 ◽  
Author(s):  
O. Adewale Osipitan ◽  
J. Anita Dille ◽  
Muthukumar V. Bagavathiannan ◽  
Stevan Z. Knezevic

AbstractKochia [Bassia scoparia(L.) A. J. Scott] is a problematic weed species across the Great Plains, as it is spreading fast and has developed herbicide-resistant biotypes. It is imperative to understand key life-history stages that promote population expansion ofB. scopariaand control strategies that would provide effective control of these key stages, thereby reducing population growth. Diversifying weed control strategies has been widely recommended for the management of herbicide-resistant weeds. Therefore, the objectives of this study were to develop a simulation model to assess the population dynamics ofB. scopariaand to evaluate the effectiveness of diverse weed control strategies on long-term growth rates ofB. scopariapopulations. The model assumed the existence of a glyphosate-resistant (GR) biotype in theB. scopariapopulation, but at a very low proportion in a crop rotation that included glyphosate-tolerant corn (Zea maysL.) and soybean [Glycine max(L.) Merr.]. The parameter estimates used in the model were obtained from various ecological and management studies onB. scoparia. Model simulations indicated that seedling recruitment and survival to seed production were more important than seedbank persistence forB. scopariapopulation growth rate. Results showed that a diversified management program, including glyphosate, could provide excellent control ofB. scopariapopulations and potentially eliminate already evolved GRB. scopariabiotypes within a given location. The most successful scenario was a diverse control strategy that included one or two preplant tillage operations followed by preplant or PRE application of herbicides with residual activities and POST application of glyphosate; this strategy reduced seedling recruitment, survival, and seed production during the growing season, with tremendous negative impacts on long-term population growth and resistance risk inB. scoparia.


Weed Science ◽  
1983 ◽  
Vol 31 (6) ◽  
pp. 889-891 ◽  
Author(s):  
P. Ashley O'Sullivan

Field experiments were conducted for 2 yr to determine the influence of picloram (4-amino-3,5,6-trichloropicolinic acid) and a commercial mixture of picloram plus 2,4-D [(2,4-dichlorophenoxy)acetic acid] (1:16, w/w) on control of wild oats (Avena fatua L. # AVEFA) with four postemergence herbicides. The phytotoxicity to wild oats of barban (4-chloro-2-butynyl m-chlorocarbanilate) or difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium) in 1981 and diclofop {2-[4-(2,4-dichlorophenoxy)-phenoxy] propanoic acid} or flamprop [N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL-alanine] in 1981 and 1982 was reduced when these herbicides were applied in a mixture with picloram plus 2,4-D. Consequently, the use of these mixtures for broad-spectrum weed control in one spray operation is not recommended. Picloram applied at a rate equivalent to the amount present in the picloram plus 2,4-D mixture did not influence the control of wild oats obtained with any herbicide, indicating that the antagonism was due to the 2,4-D component of the picloram plus 2,4-D mixture.


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