scholarly journals INTERVAL BETWEEN SEQUENTIAL HERBICIDE TREATMENTS FOR SOURGRASS MANAGEMENT

2020 ◽  
Vol 33 (3) ◽  
pp. 579-590
Author(s):  
RAFAEL ROMERO MENDES ◽  
HUDSON KAGUEYAMA TAKANO ◽  
DENIS FERNANDO BIFFE ◽  
JAMIL CONSTANTIN ◽  
RUBEM SILVÉRIO DE OLIVEIRA JUNIOR

ABSTRACT More than one herbicide application is usually necessary to manage glyphosate-resistant sourgrass in advanced stages of development efficiently during off-season fallow periods. The objective of this study was to determine the best interval between two sequential applications to control sourgrass, based on the number of days and tiller-height after the first treatment. Two experiments were conducted based on these criteria. Experiment 1 consisted of one application of glyphosate + clethodim (1140 ae ha-1 + 108 g ha-1) followed by glyphosate + clethodim or paraquat (400 g ai ha-1) at an interval of 10, 17, 24, 31, 28, or 45 days. Experiment 2 was conducted with the same herbicide treatments, but using the tiller-height as the criteria for the second application, which were 2-5, 6-10, 11-20, 21-30, and >30 cm. None of the treatments resulted in total sourgrass control during the evaluation period. Overall, treatments with glyphosate + clethodim in the second application were more efficient than paraquat. The most effective interval between sequential applications of glyphosate + clethodim was observed at 17 to 24 days. For paraquat, the best interval for the second application was 6-10 days. The most effective performances based on the tiller-height were found at 620 cm tall for glyphosate + clethodim and 6-10 cm tall for paraquat.

2019 ◽  
Vol 37 ◽  
Author(s):  
M. CASSOL ◽  
M.D. MATTIUZZI ◽  
A.J.P. ALBRECHT ◽  
L.P. ALBRECHT ◽  
L.C. BACCIN ◽  
...  

ABSTRACT: Sourgrass is one of the weeds of great economic importance in Brazil due to its difficulty of control and conditions that allow its emergence and development throughout the year. Thus, this study aimed to evaluate the effectiveness of clethodim and haloxyfop applied alone or mixed with glyphosate and other herbicides to control glyphosate-resistant sourgrass at different stages of development. For this, three experiments were conducted in the field: in experiment 1, the herbicides were applied in sourgrass plants with 6 to 8 tillers; and in experiments 2 and 3, when plants were at full flowering, with up to 18 tillers. After treatment application, visual evaluations were performed at 14, 21, 28, 35, 42, 49, and 56 days after application (DAA) in experiment 1 and at 7, 14, 21, 28, and 35 DAA in experiments 2 and 3. Also in experiment 3, the shoot of remaining plants was collected in the last control evaluation to measure the dry matter. In experiment 1, the treatment glyphosate + clethodim presented a satisfactory control close to 90%, but after 35 DAA, sourgrass plants started showing significant resprouts, decreasing the control. In experiments 2 and 3, treatments showed no control above 90% and the herbicides clethodim and haloxyfop had similar final control when in mixture with glyphosate. Therefore, the isolated herbicide application at the tested doses was not sufficient for efficient control of sourgrass at more advanced stages of development.


2006 ◽  
Vol 23 (1) ◽  
pp. 66-69 ◽  
Author(s):  
Adam H. Wiese ◽  
Daniel A. Netzer ◽  
Don E. Riemenschneider ◽  
Ronald S. Zalesny

Abstract We designed, constructed, and field-tested a versatile and unique weed compaction roller system that can be used with mechanical herbicide application for invasive weed control in tree plantations, agronomic settings, and areas where localized flora and fauna are in danger of elimination from the landscape. The weed compaction roller system combined with herbicide application generally had greater vegetation control compared with using only herbicide treatments or the unsprayed control. The roller system-herbicide treatment combination showed substantial total vegetation control two growing seasons after application without impacting diameter growth of the crop trees, which supports the need for less frequent entries into the field. The cost of the roller system was approximately $300.00.


2012 ◽  
Vol 30 (4) ◽  
pp. 861-870 ◽  
Author(s):  
N.M. Correia ◽  
F.J. Perussi ◽  
L.J.P. Gomes

The aim of this study was to assess the efficacy of S-metolachlor applied in pre-emergence conditions for the control of Brachiaria decumbens, Digitaria horizontalis, and Panicum maximum in sugar cane mechanically harvested without previous burning of the crop (green harvest) with the crop residue either left or not on the soil surface. The experiments were established in the field according to a randomized complete block design with four repetitions in a 7 x 2 split-plot scheme. In the plots, five herbicide treatments were studied (S-metolachlor at 1.44, 1.92, and 2.40 kg ha-1, clomazone at 1.20 kg ha-1, and isoxaflutole at 0.188 kg ha-1), and two control treatments with no herbicide application. In the subplots, the presence or absence of sugar cane crop residue on the soil surface was evaluated. S-metolachlor efficacy was not hampered by either 14 or 20 t ha-1 of sugar cane crop residue on the soil surface. When sugar cane crop residue was covering the soil surface, S-metolachlor at a rate of 1.44 kg ha-1 resulted in weed control similar at their larger rates, where as without the presence of crop residue, S-metolachlor controlled B. decumbens, D. horizontalis, and P. maximum at the rates of 1.92, 1.44, and 1.92 kg ha-1, respectively. The herbicides clomazone and isoxaflutole were effective for the studied species, independently of the crop residue covering the soil surface. S-metolachlor caused no visible injury symptoms to the sugar cane plant. Clomazone and isoxaflutole caused visible injuries to the sugar cane plant. None of the herbicides negatively affected the number of viable culms m² or the culm height and diameter.


2015 ◽  
Vol 29 (3) ◽  
pp. 405-411 ◽  
Author(s):  
Whitney D. Crow ◽  
Lawrence E. Steckel ◽  
Robert M. Hayes ◽  
Thomas C. Mueller

Recent increases in the prevalence of glyphosate-resistant (GR) Palmer amaranth mandate that new control strategies be developed to optimize weed control and crop performance. A field study was conducted in 2012 and 2013 in Jackson, TN, and in 2013 in Knoxville, TN, to evaluate POST weed management programs applied after harvest (POST-harvest) for prevention of seed production from GR Palmer amaranth and to evaluate herbicide carryover to winter wheat. Treatments were applied POST-harvest to corn stubble, with three applications followed by a PRE herbicide applied at wheat planting. Paraquat alone or mixed withS-metolachlor controlled 91% of existing Palmer amaranth 14 d after treatment but did not control regrowth. Paraquat tank-mixed with a residual herbicide of metribuzin, pyroxasulfone, saflufenacil, flumioxazin, pyroxasulfone plus flumioxazin, or pyroxasulfone plus fluthiacet improved control of regrowth or new emergence compared with paraquat alone. All residual herbicide treatments provided similar GR Palmer amaranth control. Through implementation of POST-harvest herbicide applications, the addition of 1,200 seed m−2or approximately 12 million seed ha−1to the soil seedbank was prevented. Overall, the addition of a residual herbicide provided only 4 to 7% more GR Palmer amaranth control than paraquat alone. Wheat injury was evident (< 10%) in 2012 from the PRE applications, but not in 2013. Wheat grain yield was not adversely affected by any herbicide application.


1998 ◽  
Vol 12 (4) ◽  
pp. 699-706 ◽  
Author(s):  
Brett R. Miller ◽  
Rodney G. Lym

Clopyralid applied to Canada thistle rosettes has provided better control in the following growing season than applications to bolted plants. The objectives of this research were to determine if using cultivation to prevent plants from bolting prior to herbicide application (the rosette technique) could be successfully incorporated into a row crop production system and to evaluate the effect of Canada thistle growth stage on the absorption and translocation of14C-clopyralid. Canada thistle control 8 mo after postharvest herbicide treatment (MAFT) using the rosette technique was similar to control when using conventional in-crop plus postharvest herbicide treatments in corn and soybean. Glyphosate and clopyralid plus 2,4-D were the most consistent postharvest herbicide treatments for Canada thistle control 8 MAFT in corn and soybean. Corn yields were similar, but soybean yields were slightly lower when Canada thistle was controlled using cultivation compared to conventional herbicide treatments.14C-clopyralid translocation to Canada thistle roots and lower shoot parts was greater when clopyralid was applied to the rosette stage than when applied to bolted Canada thistle plants. The increased translocation probably accounts for the increased Canada thistle control observed in the field. Incorporating the rosette technique into a weed management program should allow growers to control Canada thistle with less herbicide input than do standard practices.


Plant Disease ◽  
1997 ◽  
Vol 81 (7) ◽  
pp. 787-790 ◽  
Author(s):  
S. L. Reichard ◽  
R. M. Sulc ◽  
L. H. Rhodes ◽  
M. M. Loux

This study was conducted to determine whether herbicides and adjuvants registered for poste-mergence use in alfalfa have an effect on Sclerotinia crown and stem rot (SCSR). In a controlled environment, disease severity index (DSI) of alfalfa seedlings was reduced by pronamide and 2,4-DB compared with the untreated control, whereas bromoxynil and 13% sethoxydim + petroleum-based adjuvant (PBA) increased DSI. In the field, disease severity in all herbicide treatments was similar to that in untreated alfalfa. In a second controlled-environment study, pronamide and 2,4-DB reduced DSI compared with the no herbicide control when seedlings were inoculated 1 day after herbicide application, but this protective effect was not observed when seedlings were inoculated 8 days or longer after herbicide application. The results demonstrate that several herbicides are capable of suppressing or enhancing SCSR severity in a controlled environment if seedling inoculation occurs soon after herbicide application; however, the residual effect of these herbicides on SCSR appeared to be much shorter than the 4- to 6-week infection period occurring in the field.


Author(s):  
Todd Patrick McCarty ◽  
Peter G. Pappas

In many ways, fungal diseases are forgotten or neglected. Given the significantly lower frequency compared to similar bacterial etiologies across the spectrum of infectious syndromes, it makes sense that anti-bacterial agents have seen the bulk of development in recent decades. The vast majority of new antifungal medications approved for use in the past 10 years have been new versions in the same class as existing agents. Clinical mycology is crying out for new mechanisms of action in the setting of rising resistance and emergence of new organisms. Fortunately, this trend appears to be reversing. There are numerous agents in advanced stages of development offering novel dosing regimens and mechanisms of action to combat these threats. Herein we review seven antifungal agents that we hope to see come to market in the coming years to aid physicians in the treatment of mucocutaneous and invasive fungal infections.


2019 ◽  
Vol 33 (04) ◽  
pp. 620-626
Author(s):  
M. Carter Askew ◽  
Charles W. Cahoon ◽  
Alan C. York ◽  
Michael L. Flessner ◽  
David B. Langston ◽  
...  

AbstractAuxin herbicides are used in combinations to control glyphosate-resistant horseweed preplant burndown. Herbicide labels for 2,4-D–containing products require a 30-d rotation interval for planting cotton cultivars not resistant to 2,4-D. Dicamba labels require an accumulation of 2.5 cm of rain plus 21 d per 280 g ae ha–1 rotation interval for planting cotton cultivars not resistant to dicamba. Previous research has shown that cotton injury caused by dicamba applied 14 d before planting was transient with little effect on cotton yield, whereas 2,4-D has little effect on cotton when applied 7 d prior to planting. Injury caused by dicamba and 2,4-D is inversely related to rainfall received between herbicide application and cotton planting. Experiments were conducted to evaluate cotton tolerance to halauxifen-methyl, a new Group 4 herbicide, applied at intervals shorter than labeled requirements. Experiments were established near Painter and Suffolk, VA, and Belvidere, Clayton, Eure, Lewiston, and Rocky Mount, NC, during the 2017 and 2018 growing seasons. Herbicide treatments included halauxifen, dicamba, and 2,4-D applied 4, 3, 2, 1, and 0 wk before planting (WBP). Visible estimates of cotton growth reduction and total injury were collected 1, 2, and 4 wk after cotton emergence (WAE). Cotton stand and percentage of plants with distorted leaves were recorded 2 and 4 WAE. Cotton plant heights were recorded 4 and 8 WAE. Halauxifen was less injurious (9%) than dicamba (26%) or 2,4-D (21%) 2 WAE when herbicides were applied 0 WBP. Cotton stand reduction 2 WAE by halauxifen was less than 2,4-D and dicamba when applied 0 WBP. Injury observed from herbicides applied 1, 2, 3, and 4 WBP was minor, and no significant differences in cotton stand were observed. Early-season cotton injury was transient, and seed cotton yield was unaffected by any treatment.


Weed Science ◽  
2019 ◽  
Vol 67 (2) ◽  
pp. 189-194 ◽  
Author(s):  
Michael H. Ostlie ◽  
Dale Shaner ◽  
Melissa Bridges ◽  
Phillip Westra

AbstractCereal rye (Secale cerealeL.) control in wheat (Triticum aestivumL.) can be difficult with existing selective herbicides. High phenotypic diversity within populations coupled with suboptimal herbicide application conditions leads to varying degrees of control with herbicide treatments. The following research focused on the consequence of low temperature on imazamox fate inS. cereale. A greenhouse study was conducted to determine the number of warm-temperature days required for imazamox to controlS. cereale. Absorption, translocation, and metabolism of imazamox was evaluated under warm (22/18C) and cold (4/4C) temperatures to identify changes to the fate of imazamox under different environmental conditions. In greenhouse conditions, more than 5 d of warm temperature following herbicide application was required to achieve 80%S. cerealemortality. Absorption of imazamox was reduced 20% whenS. cerealewas subjected to cold compared with warm temperatures. Only 10% of applied imazamox was moved from the treated leaf in continuous cool temperatures compared with greater than 60% in warm conditions. In cold conditions, imazamox content increased in all tested plant parts evaluated for the duration of the study, whereas in warm conditions, imazamox concentrations decreased in root and crown tissues after 3 d. Imazamox behavior was affected more by temperature thanS. cerealegrowth stage.Secale cerealemetabolism of imazamox was reduced, but not stopped in cold temperatures. After 6 d, only a 10% difference in intact imazamox remained between temperature treatments. In cold temperatures, reduced absorption and translocation, coupled with continued metabolism, allow plants to recover from an otherwise lethal imazamox treatment.


2017 ◽  
Vol 31 (6) ◽  
pp. 863-869 ◽  
Author(s):  
Shawn C. Beam ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Jonathan R. Schultheis ◽  
Sushila Chaudhari

Field studies were conducted to determine the influence of herbicides on the development of internal necrosis (IN) in sweetpotato storage roots. In a slip propagation study, herbicide treatments included PRE application (immediately after covering seed roots with soil) of clomazone (0.42, 0.84 kg ai ha-1), flumioxazin (0.11, 0.21 kg ai ha-1), fomesafen (0.28, 0.56 kg ai ha-1), linuron (0.56, 1.12 kg ai ha-1),S-metolachlor (0.8, 1.6 kg ai ha-1), flumioxazin plusS-metolachlor (0.11 + 0.8 or 1.6 kg ha-1), and napropamide (1.12, 2.24 kg ai ha-1), and POST application (2 to 4 wk prior to cutting slips) of ethephon (0.84, 1.26 kg ai ha-1) and paraquat (0.14, 0.28 kg ai ha-1). In a field production study, flumioxazin, fomesafen, linuron, and paraquat were applied PREPLANT (one d prior to sweetpotato transplanting), clomazone,S-metolachlor, and napropamide were applied PRE [4 d after transplanting (DAP)], flumioxazin PREPLANT followed by (fb) S-metolachlor PRE, and ethephon applied POST (2 wk prior to harvest). Herbicide rates were similar to those used in the slip propagation study. Yield of sweetpotato in both studies was not affected by herbicide treatment. In both studies, IN incidence and severity increased with time and was greatest at 60 d after curing. No difference was observed between herbicide treatments for IN incidence and severity in the slip production study which indicates herbicide application at time of slip propagation does not impact the development of IN. In the field production study, the only treatment that increased IN incidence compared to the nontreated was ethephon with 53% and 2.3 incidence and severity, respectively. The presence of IN affected roots in nontreated plots indicates that some other pre- or post-curing factors other than herbicides are responsible for the development of IN. However, the ethephon application prior to sweetpotato root harvest escalates the development of IN.


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