Response of Giant Reed (Arundo donax) to Asulam and Trifloxysulfuron

2012 ◽  
Vol 26 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Dennis C. Odero ◽  
Robert A. Gilbert
Keyword(s):  
Dose Response ◽  
Dry Weight ◽  
South Florida ◽  
Giant Reed ◽  
Bioenergy Crop ◽  
Invasive Potential ◽  
Complete Control ◽  
Production Region ◽  
Shoot Dry Weight ◽  
Research And Education

Giant reed has been proposed as a bioenergy crop in the sugarcane production region of south Florida, where it has a high invasive potential. In an effort to limit future invasion of giant reed escapes in sugarcane, currently labeled sugarcane herbicides asulam and trifloxysulfuron were evaluated for its management. Greenhouse and field dose–response studies were conducted at the Everglades Research and Education Center in Belle Glade, FL, between 2010 and 2011. Herbicides were applied at rates ranging from 0.46 to 7.4 kg ha−1asulam and 2 to 32 g ha−1trifloxysulfuron, which represent 0.125× to 2× sugarcane labeled use rates, respectively. In the greenhouse, asulam and trifloxysulfuron reduced giant reed relative shoot dry weight by a maximum of 50% at 21 d after treatment (DAT). The probability of giant reed resprouting 35 d following herbicide treatment was greater for trifloxysulfuron when compared with asulam. In the field, it was predicted that a maximum of 69 and 55% giant reed control occurred with application of asulam and trifloxysulfuron, respectively, at 14 DAT. Relative shoot dry weight of giant reed treated with asulam and trifloxysulfuron was reduced by a maximum of 43% at 42 DAT. Application of asulam and trifloxysulfuron did not provide complete control of giant reed at twice the labeled sugarcane use rate, indicating that control of established giant reed in sugarcane with currently available herbicides would not be an option.

Confirmation of Glyphosate-Resistant Horseweed (Conyza canadensis) in Montana Cereal Production and Response to POST Herbicides

2017 ◽  
Vol 31 (6) ◽  
pp. 799-810 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha ◽  
Amit J. Jhala
Keyword(s):  
Great Plains ◽  
Dose Response ◽  
Best Management Practices ◽  
Management Practices ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Greenhouse Study ◽  
Whole Plant ◽  
Cereal Production ◽  
Sites Of Action

In recent years, horseweed has become an increasing problem in Montana. To confirm and characterize the level of glyphosate resistance, seeds were collected from putative glyphosate-resistant (GR) horseweed (GR-MT) plants in a wheat–fallow field in McCone County, MT. Known GR (GR-NE) and glyphosate-susceptible (GS-NE) horseweed accessions from Lincoln, NE, were included for comparison in dose–response and shikimate accumulation studies. Whole-plant glyphosate dose–response experiments conducted at the early- (5- to 8-cm diameter) and late- (12- to 15-cm diameter) rosette stages of horseweed indicated that GR-MT accessions had a 2.5- to 4.0-fold level of resistance to glyphosate relative to the GS-NE accession, on the basis of shoot dry weight (GR50values). The level of resistance was 3.1- to 7.9-fold on the basis of visually assessed injury estimates (I50values). At the whole-plant level, about 2.1- to 4.5-fold higher shikimate accumulation was observed in the GS-NE accession compared with the GR-MT and GR-NE accessions over a 10-d period after glyphosate was applied at 1,260 g ae ha−1. In a separate greenhouse study, all three horseweed accessions were also screened with alternate POST herbicides registered for use in wheat–fallow rotations. The majority of the tested herbicides provided ≥90% injury at the field-use rates for all three horseweed accessions 3 wk after treatment. This is the first published report on the occurrence of GR horseweed in Montana cereal production. Increased awareness and adoption of best management practices, including the use of diversified (based on multiple sites of action) herbicide programs highlighted in this study, would aid in mitigating the further spread of GR horseweed in the cereal production fields of the U.S. Great Plains.

Tolerance Evaluation of Vegetatively Established Miscanthus × giganteus to Herbicides

2013 ◽  
Vol 27 (4) ◽  
pp. 735-740 ◽  
Author(s):  
Xiao Li ◽  
Timothy L. Grey ◽  
Brian H. Blanchett ◽  
R. Dewey Lee ◽  
Theodore M. Webster ◽  
...  
Keyword(s):  
Weed Management ◽  
Dry Weight ◽  
Field Studies ◽  
The United States ◽  
Invasive Potential ◽  
Shoot Height ◽  
Shoot Dry Weight ◽  
Miscanthus Giganteus ◽  
Reduced Height ◽  
Giant Miscanthus

Giant miscanthus is under consideration as a biofuel crop in the United States; however, there is little information on weed management for the establishment and survival of this crop. Therefore, greenhouse and field studies using ornamental pots were conducted in summer 2011 at Tifton, GA, with the objective of screening potential PPI, PRE, and POST herbicides and herbicide combinations for giant miscanthus when establishing from vegetative rhizomes. For the POST treatments, giant miscanthus was established from rhizomes in 7.6-L containers in the field and treated with 27 POST herbicides to evaluate efficacy. Thifensulfuron, metsulfuron, tribenuron, chlorimuron, halosulfuron, rimsulfuron, cloransulam, pinoxaden, bentazon, and metribuzin did not significantly lower shoot height, reduce shoot dry weight, or increase injury compared with nontreated control (NTC) when evaluated at 4 wk after treatment. Nicosulfuron, trifloxysulfuron, sulfometuron, clodinafop, fluazifop, and pyrithiobac caused the greatest injury, reduced plant height, and reduced dry weights compared with the NTC. Sethoxydim, diclofop, flumioxazin, imazamox, imazapic, and imazethapyr decreased plant heights or resulted in increased injury. PPI and PRE treatments included 21 herbicides and herbicide combinations applied at two rates. Results indicated that most treatments containing atrazine, metribuzin, pendimethalin, acetochlor, metolachlor, and mesotrione did not injure or stunt growth; however, EPTC at 4.5 kg ai ha−1 significantly reduced height and dry weight and oxadiazon resulted in greater injury compared with NTC at both rates. These results indicate that PPI, PRE, and POST herbicides can be utilized for establishment of giant miscanthus from vegetative rhizomes. Considering the invasive potential of giant miscanthus, several POST herbicides evaluated in this study such as fluazifop, pyrithiobac, and sulfometuron may be viable options to control this species if it becomes invasive.

scholarly journals Dose-response curves of Lolium multiflorum biotypes resistant and susceptible to clethodim

2013 ◽  
Vol 31 (4) ◽  
pp. 887-892 ◽  
Author(s):  
L. Vargas ◽  
D.S. Fraga ◽  
D. Agostinetto ◽  
F. Mariani ◽  
T.V. Duarte ◽  
...  
Keyword(s):  
Dose Response ◽  
Chemical Control ◽  
Lolium Multiflorum ◽  
Dry Weight ◽  
Rio Grande Do Sul ◽  
Response Curves ◽  
Main Method ◽  
Shoot Dry Weight ◽  
Repeated Use ◽  
Dose Response Curves

Chemical control with herbicides, especially glyphosate, is the main method used to control ryegrass. However, the repeated use of glyphosate has selected resistant ryegrass biotypes. Thus, the ACCase inhibitor herbicides have become the main alternative to control glyphosate-resistant biotypes, being widely used by farmers in Rio Grande do Sul. Repeated use of ACCase inhibitors, in turn, have selected ryegrass biotypes resistant to this herbicide mechanism. Thus, the objective of this study was to evaluate the response of ryegrass biotypes to different clethodim rates by dose-response curves. Increasing doses (0, 12, 24, 48, 72, 96, 144 and 192 g a.i. ha-1) of the herbicide clethodim were applied at the 3-4 ryegrass leaf stage. The variables control at 14 and 28 days after treatment (DAT) and shoot dry weight were evaluated. The data were fitted by nonlinear regression log-logistic and C50 and GR50 were calculated based on the equation. The resistance factor was obtained by the ratio of C50 or GR50 of the resistant biotype by matching the susceptible biotype. Based on the equation parameters, the doses of GR50 64.7 and 234.5 g a.i. ha-1 clethodim and C50 11.2 and 172.1 g a.i. ha-1 clethodim were obtained, at 28 DAT for the susceptible and resistant biotypes, respectively. The ryegrass biotype denominated Cotril is resistant to clethodim, being controlled with a dose 15.3 times greater than that of the susceptible biotype, and a 50% reduction of this biotype occurs with a dose 3.62 times higher than that of the susceptible one.

Confirmation, Characterization, and Management of Glyphosate-Resistant Ragweed Parthenium (Parthenium hysterophorus L.) in the Everglades Agricultural Area of South Florida

2015 ◽  
Vol 29 (2) ◽  
pp. 233-242 ◽  
Author(s):  
Jose V. Fernandez ◽  
Dennis C. Odero ◽  
Gregory E. MacDonald ◽  
Jason Ferrell ◽  
Lyn A. Gettys
Keyword(s):  
Weed Control ◽  
Dose Response ◽  
Glyphosate Resistance ◽  
South Florida ◽  
Agricultural Area ◽  
Complete Control ◽  
Everglades Agricultural Area ◽  
Significant Difference ◽  
Lack Of Control ◽  
Treated Leaf

Growers have observed lack of control of ragweed parthenium with glyphosate at 0.84 kg ae ha−1 used for weed control in noncrop areas and fallow fields in the Everglades Agricultural Area (EAA) of South Florida. Therefore, studies were conducted to (1) confirm and characterize the level of glyphosate resistance in ragweed parthenium from the EAA, (2) determine if reduced absorption or translocation is the mechanism of resistance of ragweed parthenium to glyphosate, and (3) evaluate the efficacy of POST herbicides commonly used in cultivated and noncrop areas for broadleaf weed control on flowering ragweed parthenium at the full and half labeled rate. A dose-response bioassay was used to determine the response of the rosette ragweed parthenium biotype from the EAA (resistant) and a susceptible biotype from Stoneville, MS, to glyphosate. The bioassay showed that the resistant biotype was 40- to 43-fold less sensitive to glyphosate when compared to the susceptible biotype. There was no significant difference in glyphosate absorption or translocation from the treated leaf to the rest of the plant 168 h after treatment between resistant and susceptible biotypes. This shows that absorption or translocation is not a mechanism of glyphosate resistance by ragweed parthenium. Saflufenacil + dimethenamid-P and hexazinone provided rapid and complete control of flowering ragweed parthenium 3 wk after treatment (WAT). Aminocyclopyrachlor + chlorsulfuron and aminopyralid at the full and the half label rates provided 100% control of ragweed parthenium by 9 WAT. Clopyralid, 2,4-D amine, and glufosinate at the full label rate provided 89 to 98% control of ragweed parthenium 9 WAT. Control of ragweed parthenium 9 WAT was < 75% with flumioxazin, fomesafen, glyphosate, imazapic, imazethapyr, mesotrione, oxyfluorfen, and paraquat, irrespective of use rate.

Paraquat resistance in horseweed (Conyza canadensis) and Virginia pepperweed (Lepidium virginicum) from Essex County, Ontario

Weed Science ◽  
1998 ◽  
Vol 46 (2) ◽  
pp. 200-204 ◽  
Author(s):  
Alida Smisek ◽  
Colleen Doucet ◽  
Martha Jones ◽  
Susan Weaver
Keyword(s):  
Dose Response ◽  
Dry Weight ◽  
Repeated Exposure ◽  
Conyza Canadensis ◽  
Essex County ◽  
Shoot Dry Weight ◽  
Paraquat Resistance ◽  
Resistant Population ◽  
Susceptible Populations ◽  
Fruit Orchards

Populations of horseweed and Virginia pepperweed resistant to the herbicide paraquat were found in several fruit orchards in Essex County, Ontario, Canada, where paraquat had been applied four to five times per year for at least 10 yr. Dose–response experiments were conducted in the greenhouse for each species, using 2-to 4-mo-old plants from populations that had received repeated exposure to paraquat and those that had not. The paraquat dose that reduced shoot dry weight by 50% (ED50) was estimated for each population. Resistant populations of horseweed had ED50 values 25 to 35 times higher than susceptible populations. A resistant population of Virginia pepperweed had an ED50 10 times higher than susceptible populations.

scholarly journals Variable response of kochia [Kochia scoparia (L.) Schrad.] to auxinic herbicides dicamba and fluroxypyr in Montana

2015 ◽  
Vol 95 (5) ◽  
pp. 965-972 ◽  
Author(s):  
Prashant Jha ◽  
Vipan Kumar ◽  
Charlemagne A. Lim
Keyword(s):  
Great Plains ◽  
Dose Response ◽  
Weed Management ◽  
Dry Weight ◽  
Northern Great Plains ◽  
Variable Response ◽  
Kochia Scoparia ◽  
Management Tools ◽  
Herbicide Resistant ◽  
Shoot Dry Weight

Jha, P., Kumar, V. and Lim, C. A. 2015. Variable response of kochia [Kochia scoparia (L.) Schrad.] to auxinic herbicides dicamba and fluroxypyr in Montana. Can. J. Plant Sci. 95: 965–972. Herbicide-resistant kochia is an increasing concern for growers in the Northern Great Plains of United States and Canada. The objective of the research was to characterize the response of the three putative auxinic herbicide-resistant kochia inbreds (derived from accessions collected from wheat/chemical fallow fields in northern Montana) to dicamba and fluroxypyr relative to a susceptible (SUS) inbred. A dicamba dose-response study indicated that the three putative resistant inbreds (Chot-01, Chot-02, and Chot-03) had R/S ratios of 1.3 to 6.1 based on the visible control response (I50 values), and R/S ratios of 1.5 to 6.8 based on the shoot dry weight response (GR50 values). Dose-response experiments with fluroxypyr determined I50 R/S ratios of 1.4 to 5.7 and GR50 R/S ratios of 1.6 to 4.0 for the three putative resistant inbreds. The selected inbreds showed variable symptomology (phenotype) in response to dicamba and fluroxypyr. Among the three inbreds, Chot-01 exhibited the least epinasty, stem curling/swelling, and chlorosis/necrosis symptoms, and was resistant to dicamba and fluroxypyr. Growers should diversify their weed management tools to manage further spread of auxinic or multiple herbicide-resistant kochia in the region.

Assessing Herbicide Phytotoxicity with Covariance Analysis

1990 ◽  
Vol 4 (4) ◽  
pp. 828-832 ◽  
Author(s):  
S. Kent Harrison ◽  
Emilie E. Regnier
Keyword(s):  
Dose Response ◽  
Treatment Effects ◽  
Dry Weight ◽  
Leaf Length ◽  
Covariance Analysis ◽  
Standard Analysis ◽  
Response Variable ◽  
Shoot Dry Weight ◽  
Statistical Precision ◽  
Corn Seedling

Greenhouse experiments were conducted to determine the statistical precision of estimating herbicide dose-response treatment effects by covariance analysis (ANOCOVA) relative to standard analysis of variance (ANOVA). Analyses of corn seedling response to the translocated herbicides fluazifop-P, sethoxydim, and quizalofop at 10 to 60 g ai ha-1 indicated that treatment effects were estimated with 26 to 116% greater precision by ANOCOVA than ANOVA. Covariance analyses of treatment effects for corn response to the contact herbicides paraquat, acifluorfen, and lactofen at 50 to 300 g ai ha-1 gave 8 to 13% greater precision than ANOVA. Gains in precision by ANOCOVA for all experiments were generally greatest when shoot dry weight was analyzed as the response variable and pretreatment fifth leaf length served as the covariate.

scholarly journals Differential susceptibility of biotypes of conyza sumatrensis to Chlorimuron-ethyl herbicide

2014 ◽  
Vol 32 (2) ◽  
pp. 427-435 ◽  
Author(s):  
F.M. Santos ◽  
L. Vargas ◽  
P.J. Christoffoleti ◽  
D. Agostinetto ◽  
F. Mariani ◽  
...  
Keyword(s):  
Dose Response ◽  
Weed Management ◽  
Leaf Growth ◽  
Differential Susceptibility ◽  
Dry Weight ◽  
Response Curves ◽  
Shoot Dry Weight ◽  
Randomized Design ◽  
Chlorimuron Ethyl ◽  
Dose Response Curves

Horseweed (Conyza spp.) is an annual weed, infesting soybean crops in southern Brazil, with chlorimuron-ethyl being one of the most commonly used herbicides for its control. However, in recent soybean harvests, an unsatisfactory control of this weed using this herbicide was observed, generating suspicion regarding the selection of resistant biotypes. The objective of this study was to evaluate the susceptibility of horseweed biotypes to the herbicide chlorimuron-ethyl. Two experiments were conducted in a greenhouse; in the first one, the biotypes were selected selected, and the second experiment was arranged in a 5 x 5 factorial in a completely randomized design with four replications. The treatments used in the preparation of the dose response curves were doses of the herbicide chlorimuron-ethyl (0.0, 1.56, 3.13, 6.25, 12.5, and 25 g ha-1), applied on the five horseweed biotypes at the 3-4 leaf growth stage. The variables evaluated were visual control percentage and shoot dry weight, compared to the control without herbicide application, and plant acetolactate accumulation. It was concluded that there is a differential susceptibility among the biotypes at doses of less than 20 g ha-1 (dose response curves), which indicates low-level resistance. The practical consequences are the indications of chlorimuron-ethyl application at the maximum doses recomended and that the practice of rotating mechanisms of action must be used in the chemical weed management of these areas.

Plant mortality and seedling recruitment responses to flupropanate in grassland populations of Nassella trichotoma

2017 ◽  
Vol 70 ◽  
pp. 160-164 ◽  
Author(s):  
G.W. Bourdôt ◽  
S. Jackman ◽  
D.J. Saville
Keyword(s):  
New Zealand ◽  
Dose Response ◽  
Sodium Salt ◽  
Seedling Recruitment ◽  
Residual Activity ◽  
Application Rate ◽  
Plant Mortality ◽  
Complete Control ◽  
Bio Synthesis

Flupropanate (sodium 2,2,3,3 tetrafluoropropanate), a slow-acting lipid bio- synthesis-inhibiting herbicide, was recently registered in New Zealand as Taskforce (745 g/L flupropanate as the sodium salt) for the selective and long-term control of Nassella trichotoma (nassella tussock) in pastures. In five dose-response experiments in permanent hill pastures in Canterbury, conducted between 2012 and 2016, we measured the efficacy of the herbicide against established plants of N. trichotoma and its residual activity against recruiting seedlings. Mortality, as an average across the five sites, was 93% 1.5 years after applying 1.49 kg flupropanate/ha (the label-recommended rate), and 100% at 2.98 kg/ha. This indicates that an application rate higher than the label rate will be necessary for complete control of a N. trichotoma infestation. The presence of 1,000 and 6,250 visible seedlings of N. trichotoma/ha in the autumn 3.2 and 2.1 years after applying 1.49 kg flupropanate/ha (at a Greta Valley and Scargill site respectively) indicates that the herbicide’s soil residues had decayed within 12 months to a concentration lower than necessary to kill the germinating seedlings of N. trichotoma.

Cell Size and Pretransplant Nutritional Conditioning Influences Early Vine Growth and Yield of Transplanted Watermelon

HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 594e-594
Author(s):  
Charles J. Graham
Keyword(s):  
Cell Volume ◽  
Significant Influence ◽  
Field Performance ◽  
Dry Weight ◽  
Soluble Solids ◽  
Growth And Yield ◽  
Average Weight ◽  
Shoot Dry Weight ◽  
Solids Concentration ◽  
Soluble Solids Concentration

Research is needed to better understand the influence of cell volume and fertility on watermelon transplant size and field performance in order to determine the most economic production practices. `Jubilee' watermelon transplants were grown using a 4 x 4 factorial experimental design consisting of 4 cell volumes (30.7, 65.5, 147.5, and 349.6 cm3) and 4 fertility rates (0, 1/4, 1/2, and full-strength Hoagland's solution). Transplant shoot dry weight significantly increased as cell volume and fertility increased. Increasing cell volume linearly increased watermelon number/ha and tons/ha for early and total harvest in 1995. The average weight per watermelon significantly increased for early-harvested fruit but not for total harvest as cell volume increased in 1995. Soluble solids concentration linearly increased with increasing cell volume for early and total harvests in 1995. Cell volume had no significant influence on the harvest parameters measured in 1997. In 1995, increasing fertility linearly increased watermelon number/ha and tons/ha for early harvests. Increasing fertility increased the soluble solids concentration linearly for early-harvested watermelons in 1997 but not in 1995. Fertility rate had no significant influence on any of the other harvest parameters measured in 1995 and 1997. The growing conditions and disease pressure in 1997 reduced melons/ha, yield, and soluble solids content when compared to 1995 values. The half-strength Hoagland's solution produced the greatest number of watermelons/ha, tons/ha, and the highest soluble solids concentration in 1995 and 1997. Pretransplant nutritional conditioning had no significant effect on total `Jubilee' watermelon production in Louisiana for 1995 and 1997.

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