Tank Mix Research Articles

Integrated weed management in garlic with and without rice straw mulch

A field experiment was conducted at AICRP on Weed Management Farm, BACA, AAU, Anand Gujarat during two consecutive Rabi season of 2016–17 and 2017–18 on loamy sand soil to study the effect of integrated weed management in garlic with and without rice straw mulch. The experiment was laid out in Split Plot design (SPT) with three replications. Rice straw mulch 5.0 t/ha applied after planting in conjunction with either application of oxyfluorfen 240 g/ha PE fb HW at 60 DAP or tank mix application of pendimethalin 500 g/ha + oxyfluorfen 120 g/ha EPoE recorded significantly lower density and dry weight of weeds at harvest with higher weed control efficiency (91.9 and 85.9%, respectively), bulb weight (17.3 and 14.0 g/bulb, respectively), bulb yield of garlic (8.83 and 7.91 t/ha, respectively) along with the highest net return and B:C ratio.

Effect of herbicides and their combinations on weeds, productivity and profitability of maize in rainfed sub-tropics of Jammu

A field experiment was conducted at Advanced centre for rainfed agriculture, Rakh Dhiansar of Sher-e- Kashmir University of Agricultural Sciences and Technology of Jammu during the crop growing seasons of 2016 and 2017 to identify the best herbicide option for weed management in maize (Zea mayz L.). Fifteen treatments were tested in randomised block design replicated thrice. The post-emergence treatment (PoE) of tembotrione 100 g/ha + atrazine tank mix formulation 750 g/ha at 15–20 days after sowing (DAS) has recorded highest weed control efficiency (93.22 and 93.71% during 2016 and 2017, respectively) followed by tembotrione 100 g/ha + atrazine 500 g/ha at 15–20 days after sowing (DAS) and sequential application of atrazine 1000 g/ha 0–3 DAS fb tembotrione 100 g/ha 15–20 DAS. Higher maize grain yield was recorded (3.64 t/ha and 3.74 t/ha during 2016 and 2017, respectively) with weed free which was statically at par with tembotrione 100 g/ha + atrazine 500 g/ha at 15–20 DAS, tembotrione 100 g/ha + atrazine 750 g/ha at 15–20 DAS, tembotrione 100 g/ha + halosulfuron 67.5 g/ha at 15–20 DAS, tembotrione 100 g/ha+ halosulfuron 52.5 g/ha at 15–20 DAS, atrazine 1000 g/ha 0–3 DAS fb metribuzin 250 g/ha 15–20 DAS, atrazine 1000 g/ha 0–3 DAS fb tembotrione 100 g/ha 15–20. B: C ratio (3.11 and 3.12 in 2016 and 2017 respectively) was high with PoE application of tembotrione 100 g/ha + atrazine 500 g/ha.

Multiple season-long sprays of ethephon or NAA combined with calcium chloride on Honeycrisp: II. Effect on fruit mineral concentrations and incidence of bitter pit

Honeycrisp apple trees are highly prone to biennial bearing and bitter pit (BP). This 3-y study tested the hypothesis that tank mix sprays of ethephon (ETH), naphthaleneacetic acid (NAA), and 1-aminocyclopropane carboxylic acid (ACC) combined with calcium chloride (CaCl2) can mitigate these production problems. Mature ‘Honeycrisp’ were treated with either three of six applications of 150 mg.L-1 ETH, 5 mg.L-1 NAA or two of five applications of 150 mg.L-1 ACC, all tank-mixed with and without CaCl2 and applied at 10-d intervals starting 21–26 June over three growing seasons. Fruit cortical tissue nutrient concentrations were influenced by applications of CaCl2, ETH, NAA, and ACC. In one year, Ca concentrations were significantly higher in fruit from trees treated with six sprays of ETH or NAA with CaCl2 compared with the untreated control. Compared with untreated trees, fruit Ca concentrations were 115% and 148% higher with three and six applications, respectively. Applications of CaCl2 significantly reduced the incidence and severity of BP post-harvest in two of three years when fruit tissue Ca levels were low. ETH alone also increased the incidence and severity of BP two-fold compared with the control, while early season sprays of NAA reduced BP incidence and severity compared with the untreated control. High and similar levels of BP incidence and severity were observed when six sprays of NAA were applied with or without Ca. Fruit tissue K levels were generally reduced with the addition of CaCl2, and within 1 year, K levels were higher in fruit treated with ACC. Fruit Mg concentrations generally decreased with the addition of Ca or NAA. Six applications of ACC resulted in a 30-fold increase in fruit Mg concentrations compared to the untreated control. Tank mixing CaCl2 with the flower-promoting bio-regulators ETH and NAA proved to effectively reduce BP and increase fruit tissue Ca levels. This approach would offer cost savings when repeat sprays of each are required on a bi-weekly basis.

Performance of different tank mix herbicides for broad-spectrum weed control in soybean [Glycine max (L.) Merrill

A field experiment was conducted at the Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology -Udaipur during Kharif season 2015 and 2016 to test the efficacy of different herbicide and herbicide mixtures against weeds in soybean. Monocot weeds were predominant (57.68 %) in the experimental field compared to Broad leaved weeds (42.31 %). However, Echinochloa colona (40.55 %) and Corchorus olitorius (23.68%) were dominant in soybean at 30 DAS. Among different weed control treatments, post-emergence and tank mix combination of propaquizafop + imazethapyr (75+75 g ha-1) and imazethapyr + quizalofop-ethyl (75+60 g ha-1) at 21 DAS were most effective in respect of reducing weed density, weed biomass, nutrient removal by weed and improving yield attributes, yield and quality of soybean compared to other treatments. Highest seed yield (2271 kg ha-1), Haulm yield (3127 kg ha-1) of soybean and maximum net return ( 51550/ha) were also recorded with propaquizafop 75 g ha-1 + imazethapyr 75 g ha-1 followed by imazethapyr + quizalofop-ethyl (75+60 g ha-1). Further, they were also found responsible for highest uptake of N, P and K in soybean and lowest uptake of these plant nutrients by weeds.

Differential Response of Fall Panicum (Panicum dichotomiflorum) Populations in Florida Sugarcane to Asulam

AbstractSugarcane growers in Florida have been reporting reduced control of fall panicum with asulam, the main herbicide used for POST grass control. Therefore, outside container experiments were conducted to determine the response of four fall panicum populations from Florida to asulam applied alone and to evaluate whether tank-mix combination with trifloxysulfuron enhances control. Asulam was applied at 230 to 7,400 g ai ha−1, corresponding to 1/16 to 2X the maximum labeled rate for a single application in sugarcane, with or without combination with trifloxysulfuron at 16 g ai ha−1. Three fall panicum populations were collected from fields in which reduced control had been reported, while one population was from a field not used for sugarcane production but adjacent to a sugarcane field. The potency of asulam based on ED50values (the rate required to cause 50% dry weight reduction at 28 d after treatment) ranged from 2,249 to 5,412 g ha−1for tolerant populations with reported reduced fall panicum control compared with 1,808 g ha−1for the susceptible population from the field not used for sugarcane production, showing that the latter was most sensitive to asulam. Addition of trifloxysulfuron to asulam increased potency on fall panicum by 5- to 15-fold, indicating that the tank mix enhanced dry weight reduction for all populations. The probability of fall panicum survival (regrowth after aboveground biomass harvesting) at the labeled rate of asulam ranged from 2% to 47% compared with 0% to 6% when trifloxysulfuron was added to the tank mix. Our results show differential response of fall panicum populations in Florida to asulam, which can be overcome by tank mixing with trifloxysulfuron even for populations that are difficult to control in sugarcane, but no evolution of resistance to asulam.

The efficiency of foliar treatments of grain crops and potatoes with humic preparation Rostock

Aim: This article describes the results of four field experiments on the effect of foliar treatment with humic preparation Rostock in different phases of the development of spring wheat and oats, and potato varieties of different ripeness groups. Foliar treatment with humic preparation Rostock can be carried out on crops in all phases of development, but the effect in the flowering stage is weaker. Materials and Methods: Experiments on the effect of foliar treatments of humic preparation Rostock on spring wheat and oats were carried out on industrial crops of training experimental farm. Results: All the studied potato varieties have responded to foliar treatment with the Rostock in a tank mixture with an insecticide to increase yield and quality of tubers. Conclusion: Foliar treatment of crops with humic preparation Rostock can be carried out at all phases of development, but the effect at the flowering stage is weaker. All the studied potato varieties have effectively responded to foliar treatment with the Rostock in a tank mix with insecticide.

Spray Drift from a Conventional Axial Fan Airblast Sprayer in a Modern Orchard Work Environment.

Pesticide spray drift represents an important cause of crop damage and farmworker illness, especially among orchard workers. We drew upon exposure characteristics from known human illness cases to design a series of six spray trials that measured drift from a conventional axial fan airblast sprayer operating in a modern orchard work environment. Polyester line drift samples (n = 270; 45 per trial) were suspended on 15 vertical masts downwind of foliar applications of zinc, molybdenum, and copper micronutrient tracers. Samples were analyzed using inductively coupled plasma mass spectrometry and resulting masses were normalized by sprayer tank mix concentration to create tracer-based drift volume levels. Mixed-effects modeling described these levels in the context of spatial variability and buffers designed to protect workers from drift exposure. Field-based measurements showed evidence of drift up to 52 m downwind, which is approximately 1.7 times greater than the 30 m (100 ft) 'Application Exclusion Zone' defined for airblast sprayers by the United States Environmental Protection Agency Worker Protection Standard. When stratified by near (5 m), mid (26 m), and far (52 m) distances, geometric means and standard deviations for drift levels were 257 (1.8), 52 (2.0), and 20 (2.3) µl, respectively. Fixed effect model coefficients showed that higher wind speed [0.53; 95% confidence interval (CI): 0.35, 0.70] and sampling height (0.16; 95% CI: 0.11, 0.20) were positively associated with drift; increasing downwind distance (-0.05; 95% CI: -0.06, -0.04) was negatively associated with drift. Random effects showed large within-location variability, but relatively few systematic changes for individual locations across spray trials after accounting for wind speed, height, and distance. Our study findings demonstrate that buffers may offer drift exposure protection to orchard workers from airblast spraying. Variables such as orchard architecture, sampling height, and wind speed should be included in the evaluation and mitigation of risks from drift exposure. Data from our study may prove useful for estimating potential exposure and validating orchard-based bystander exposure models.

Assessment of Integrated Weed Management Approaches on Asphodelus tenuifolius in Chickpea

ABSTRACT: Chickpea is the third most important crop of rainfed areas of Pakistan, and it is severely affected by noxious weed Asphodelus tenuifolius. Therefore, a field trial was conducted to evaluate the effect of different allelopathic weed extracts, herbicides and mulches in controlling A. tenuifolius and other associated weeds in chickpea at “District Karak” Khyber Pakhtunkhwa-Pakistan. The experiment was carried out in a Randomized Complete Block Design (RCBD) and replicated thrice using a chickpea cultivar (Chattan) which was grown for the experimental trial. There were 9 treatments along with control for comparison. The treatments Stomp 330 EC (Pre-emergence) at 2.5 L ha-1, Fenoxaprop-p-ethyl, Bromoxanil+MCPA (Tank mix), Starane-M, mulching (Eucalyptus leaves), mulching (Wheat straw mulch), allelopathic weed extract (A. tenuifolius) + Stomp, allelopathic weed extract (Cyperus rotundus), allelopathic weed extract (Sorghum halepense) and control treatment were used in this trial. Data were recorded on A. tenuifolius density m-2 before and after application of weed management practices (m-2), A.tenuifolius fresh weight (m-2), seed yield (kg.ha-1), biological yield (kg ha-1) and cost-benefit ratio. Weed density before weed management was found to be non-significant. The data showed that minimum A. tenuifolius density after weed management and fresh weight (m-2) were found for Stomp 330 EC (6.33 m-2 and 1.98 kg m-2), which is statistically similar to Fenoxaprop-p-ethyl 6.9 EC (10.33 m-2 and 3.03 kg m-2) while maximum A. tenuifolius density and fresh weight (m-2) were recorded for control plots (74.33 m-2 and 287.46 kg m-2). Maximum seed yield (1,781.7 kg ha-1), biological yield (3,823 kg ha-1) and cost-benefit ratio (3.47) were recorded for plots treated with Stomp 330 EC, while the lowest seed yield (851.7 kg ha-1), biological yield (3,126.3 kg ha-1) and cost-benefit ratio (1.53) were observed for the control plot. Among the nutritive parameters in chickpea, maximum crude protein (17.40%), crude fat content (4.90%) and oil content (5.98%) were recorded for plots treated with Stomp 330 EC, while minimum crude protein (16.18%), crude fat content (4.12%) and oil content (5.01%) were found in the control plots. Thus, it is recommended that herbicides Stomp 330 EC and Fenoxaprop-p-ethyl should be used at pre-emergence at their recommended doses for control of A.tenuifolius and other associated weeds in chickpea crops.

Copper phosphite enhances efficacy of a strobilurin-triazole fungicide in controlling late season foliar diseases of soybean

Septoria brown spot (Septoria glycines) and Cercospora leaf blight (Cercospora kikuchii) are late season foliar diseases (LSFD) that co-occur every year in the soybean growing regions of Argentina. Repeated use of commercial, formulated mixes of strobilurin-triazole fungicides to control LSFD has prompted the need for tactics to increase the efficacy of these fungicide groups, thereby reduce number of applications and help prolong their life use. The objective of this study was to determine the effect of copper phosphite (CuPhi), tank-mixed with a strobilurin-triazole fungicide, in the fungicide efficacy in controlling LSFD and protecting soybean yield. Field experiments were conducted during the 2014/2015 and 2016/2017 growing seasons in six different locations in the Pampas region of Argentina. At each location, treatments consisted of: i) one foliar application of a fungicide formulated as a mix of picoxystrobin and cyproconazole (60 and 24 g a.i. ha−1, respectively), ii) one foliar application of the fungicide tank mixed with a CuPhi formulation, and iii) an untreated control. Treatment application timing in each trial was defined by an LSFD scoring system previously developed by the authors. All treatments were disposed to the experimental units in a randomized complete block design with four replications. Severity of LSFD was estimated visually as the percentage of diseased leaf area in 50 plants randomly selected in each plot at R6-R7. Grain yield (kg ha−1) was determined at physiological maturity in all trials. Severity and yield analysis using a linear mixed-effect model indicated that addition of CuPhi to the fungicide tank mix significantly reduced LSFD severity and protected yield (P < 0.05). The observed effect on disease control, however, was influenced by location in the 2014/2015 growing season, but not in the 2016/2017 growing season. The net economic return with the addition of CuPhi to the fungicide tank mix was 66.1 and 85.5 USD ha−1 higher than the fungicide formulation alone, in the 2014/15 and 2016/17 crop seasons respectively. This study shows that the addition of CuPhi to a strobilurin-triazole fungicide tank mix had a synergistic and/or additive effect in controlling LSFD in soybean and protecting grain yield. Enhanced efficacy of these fungicide groups with the addition of CuPhi could reduce the number of applications, and in consequence, help prolong life use of these fungicide modes of action.

Multiple Herbicide–Resistant Italian Ryegrass [Lolium perenneL. spp.multiflorum(Lam.) Husnot] in California Perennial Crops: Characterization, Mechanism of Resistance, and Chemical Management

AbstractItalian ryegrass [Lolium perenneL. spp.multiflorum(Lam.) Husnot] is a troublesome weedy species in many regions of California. Its control has been chiefly dependent on herbicides due to their effectiveness and practicality and, as result, herbicide-resistant populations have been selected. Poor control of a population ofL. multiflorumwith paraquat was recently reported in a prune orchard in Hamilton City, CA. A series of experiments were carried out to characterize the response of this population to several POST herbicides, study the mechanisms of resistance, and investigate alternative chemical management options in tree crops. A known susceptible (S) and the suspected resistant population (PRHC) were subjected to greenhouse dose–response experiments with clethodim, fluazifop-P-butyl, glufosinate, glyphosate, paraquat, pyroxsulam, rimsulfuron, and sethoxydim. A 310-bp fragment of theEPSPSgene containing position 106 was sequenced from PRHC and S. Field experiments were carried out in a prune orchard with PRE herbicides commonly used by perennial crop growers in California. Greenhouse dose–response experiments confirmed that PRHC is resistant to paraquat, as well as multiply resistant to clethodim and glyphosate. TheEPSPSgene of PRHC is heterozygous for glyphosate resistance at position 106, where one allele exhibited proline substituted by serine and the other by alanine. Field experiments with PRE herbicides indicated that tank mixes containing indaziflam and flumioxazin can provide adequateL. multiflorumcontrol up to 150 d after treatment. Poor weed management practices, such as overreliance on a single site of action, have frequently been associated with the selection of herbicide-resistantL. multiflorumpopulations around the world, and adequate herbicide-resistance management programs are necessary for growers to maintain economic sustainability even after evolution of herbicide-resistant weeds in their fields.

Bio-Efficacy of different tank mix herbicides for weed control in soybean [Glycine max (L.) Merrill

A field experiment was conducted at the Rajasthan College of Agriculture, MPUAT, Udaipur during Kharif season 2015 and 2016 to adjudge the efficacy of different herbicide and herbicide mixtures against weeds in soybean. Monocot weeds were predominant (55.15%) in the experimental field compared with dicot weeds (44.85%). However, Echinochloa colona (41.56%) and Trianthema portulacastrum (33.16%) were predominant in soybean but, other weeds (Cyperus rotundus, Cynodon dactylon, Commelina benghalensis, Digera arvensis, Amaranthus viridis, Physalis minima, Corchorus spp.) were also present at 60 DAS. Among different weed control treatments, post-emergence and tank mix combination of propaquizafop + imazethapyr (75+75 g ha-1) and imazethapyr + quizalofop-ethyl (75+60 g ha-1) at 21 DAS were most effective in respect of reducing weed density, weed biomass, nutrient removal by weed and promote yield attributes and yield and quality of soybean as compared to rest of weed control treatment.

3.13 Tank mixtures of insecticides and fungicides, adjuvants, additives, fertilizers and their effects on honey bees after contact exposure in a spray chamber

In agriculture honey bees may be exposed to multiple pesticides. In contrast to single applications of plant protection products (PPP), the effects of tank mixtures of two or more PPP on honey bees are not routinely assessed in the risk assessment of plant protection products. However, tank mixes are often common practice by farmers. Mixtures of practically non-toxic substances can lead to synergistic increase of toxic effects on honey bees, observed for the first time in 19921 in combinations of pyrethroids and azole fungicides. 2004 Iwasa et al. already reported that ergosterol-biosynthesis-inhibiting (EBI) fungicides strongly increase the toxicity of neonicotinoids in laboratory for the contact exposure route. Furthermore, in agricultural practice additives, adjuvants and fertilizers may be added to the spray solution. For these additives usually no informations on potential side effects on bees are available when mixed with plant protection products. Therefore, it is considered necessary to investigate possible additive or synergistic impacts and evaluate potentially critical combinations to ensure protection of bees. Here, we investigated the effects on bees of combinations of insecticides, fungicides and fertilizers under controlled laboratory conditions. A spray chamber was used to evaluate effects following contact exposure by typical field application rates. Subsequently, mortality and behaviour of bees were monitored for at least 48 h following the OECD acute contact toxicity test 2143. Dependencies of synergistic effects and the time intervals between the applications of the mixing partners were evaluated.

Manejo de plantas daninhas em milho RR® com herbicidas aplicados isoladamente ou associados ao glyphosate

The objective of this work was to evaluate the effectiveness, selectivity and effect on yield components of RR® maize as a function of herbicide application, applied alone or in a tank mix. The experiment was conducted in a randomized block design, with four replications, and treatments were control without weeding, control with weeding, glyphosate, glyphosate + [atrazine+simazine], glyphosate + [atrazine + simazine], glyphosate + tembotrione, glyphosate+mesotrione, T8-glyphosate + nicosulfuron, glyphosate + 2,4-D, glyphosate + [atrazine + S-metolachlor], T11-glyphosate + (atrazine + S-metolachlor), glyphosate + S-metolachlor, glufosinate ammonium, [nicosulfuron + mesotrione], glyphosate + [nicosulfuron + mesotrione] and glyphosate + [nicosulfuron+mesotrione] + [atrazine + simazine]. Herbicide phytotoxicity to a SYN Supremo VIP3 maize hybrid and control of Urochloa plantaginea and Digitaria ciliaris were evaluated at 7, 14, 21 and 28 days after treatment application. Prior to crop harvest, we determined weed control and, in ten plants per experimental unit, the variables related to grain yield components such as ear insertion height, ear length, number of rows and grains per rows on the ears of corn. During harvest, the mass of one thousand grains and yield were evaluated. It was observed that all herbicide treatments caused low phytotoxicity in maize, except for the post-emergence tank mix composed of glyphosate + 2,4-D and glyphosate + mesotrione, that showed the highest injuries in the four evaluated periods. Most of the herbicides showed good control of D. ciliaris and U. plantaginea, except for the pre-harvest mixture of glyphosate + 2,4-D. The post-emergence glyphosate + [atrazine + simazine] tank mix demonstrated the highest grain yield. It can be concluded, therefore, that depending on the association of herbicides, synergistic effect occurs for both weed control and crop phytotoxicity, being productivity being the main influenced variable.

A Statewide Survey of Stakeholders to Assess the Problem Weeds and Weed Management Practices in Nebraska

AbstractStakeholders were surveyed across Nebraska to identify the problem weeds and assess common weed management practices. A total of 425 responses were returned across four Nebraska extension districts (Northeast, Panhandle, Southeast, and West Central). Collectively, 61.2% of total farmed or scouted areas in Nebraska were under no-till production, and corn and soybean were the major crops (82.3% of total farmed or scouted area). Common waterhemp, horseweed, and kochia were the most problematic weeds statewide. Widespread occurrence of glyphosate-resistant (GR) weeds such as common waterhemp, horseweed, kochia, and Palmer amaranth were a serious problem in GR crop production. Additionally, 60% of growers in Nebraska reported the presence of at least one GR weed species on their farms. The most commonly used preplant burndown herbicides were 2,4-D and glyphosate, followed by saflufenacil and dicamba. In Nebraska, 74% and 59% of corn and soybean growers, respectively, were using PRE herbicides; however, more than 80% of growers were using POST herbicides for in-crop weed management. Atrazine alone or in premix or tank mix with mesotrione,S-metolachlor, or acetochlor were the most widely applied PRE herbicides in corn and grain sorghum, whereas the most commonly used PRE herbicides in soybean were the inhibitors of acetolactate synthase (ALS) and protoporphyrinogen oxidase (PPO). Glyphosate was the most frequent choice of the survey respondents as a POST herbicide in GR corn and soybean; 2,4-D was the most commonly used POST herbicide in grain sorghum and wheat. In Nebraska, only 5.2% of total crop area was planted with glufosinate-resistant crops. Most of the respondents (89%) were aware of the new multiple herbicide–resistant crops, and 80% of them listed physical drift and volatility of the auxinic herbicides as their primary concern. Forty-eight percent of survey respondents identified herbicide-resistant weed management as their primary research and extension priority.

Influence of droplet size and azoxystrobin insensitivity on frogeye leaf spot management in soybean

Field experiments were conducted in 2014 and 2015 to evaluate the influence of droplet size on foliar fungicide efficacy and leaf residue in soybean infected with Cercospora sojina, the fungal agent of frogeye leaf spot. A fungicide premix of azoxystrobin and difenoconazole was applied using two spray nozzles with varying droplet spectra. No significant differences were found among treatments in regards to visual disease ratings, soybean yield, and azoxystrobin leaf residue at 0, 2, 7, and 14 days after application. Results suggest that the potential reduction in coverage from drift-reduction nozzle technology may not negatively affect the efficacy of a tank mix of azoxystrobin and difenoconazole on frogeye leaf spot in soybean.

Response of twelve Florida cogongrass (Imperata cylindrica) populations to herbicide treatment

AbstractCogongrass [Imperata cylindrica(L.) Beauv.] is an invasive grass in the southeastern United States, and its impacts strongly affect the region, especially Florida. Herbicide strategies have been limited to glyphosate in natural areas and imazapyr in managed pine forests and non-crop areas where its soil residual activity is of less concern. This lack of options has raised concern for herbicide resistance, which has never been documented forI. cylindrica. Land managers have also reported variableI. cylindricacontrol, especially with glyphosate. To determine whether herbicide resistance was a possible explanation, we examined glyphosate response ofI. cylindricafrom 12 Florida populations. We also tested aminocyclopyrachlor with and without glyphosate and flumioxazin with glyphosate. Results indicated that herbicide performance was similar acrossI. cylindricapopulations: glyphosate and aminocyclopyrachlor reducedI. cylindricabiomass by 78% and 76%, respectively, and the combined tank mix reduced cogongrass biomass by 91%. Flumioxazin tank mixed with glyphosate did not improve control compared with glyphosate alone. There were no differences in pretreatmentI. cylindricashoot height, with the exception of two panhandle populations that were shorter. Subsequent harvests indicated few differences in shoot and root plus rhizome weights among untreated controls for almost all populations, with the exception of one of the initially shorter panhandle populations. Our findings indicate that variability in glyphosate efficacy, as suggested by managers, is unlikely due to any conferred resistance. Other abiotic factors such as drought and shade and applicator factors such as carrier water quality should be examined to better understand this issue. Additional studies examining non-target impacts of aminocyclopyrachlor should be conducted to determine its potential fit intoI. cylindricamanagement.

Transient boundary condition approach for simulating mechanical mixing in large wine tanks

Since wine is not continuously stirred during or after fermentation, it is common to use movable mixers on a variety of tank sizes or to install small, fast-rotating propeller mixers in large tanks. Many practically relevant optimization problems relate to processes occurring directly after the start of the propeller (flow field initialization period), which require 3D instationary models if CFD simulations are used. Based on traditional instationary models, these simulations are very time-consuming even on fast computers and limit the part of the flow field initialization period that can be computed. In this work, a new method was developed to speed up the transient simulation of mechanical mixing in large wine tanks. The method uses the traditional CFD techniques of moving reference frame (MRF) and several ensuing propeller rotations using sliding mesh (SM), to calculate a steady-state flow field and to compute the flow behavior in the propeller region. Subsequently, the flow’s key figures are extracted for the propeller region at multiple time-points during one rotation and continuously mapped to a new simulation starting from a flow field with zero velocity. This new approach using a transient boundary condition (BC), was validated with tank mixing experiments and literature data. In contrast to the MRF method, it allows e.g. for an estimation of minimum mixing times similar to the SM method, while computation times are reduced by a factor of up to 20 for tank-mixer scenarios evaluated in this work. For a mixing simulation in a wine tank, the new method takes only 3 days compared to more than 60 days using the traditional SM approach.

Tank Mixing Fungicides for Effectiveness Against Eastern Filbert Blight of Hazelnut

Hazelnut (Corylus avellana) production in Oregon primarily occurs on cultivars susceptible to Anisogramma anomala, the causal agent of eastern filbert blight (EFB). Management of EFB involves planting resistant cultivars, removal of cankered limbs, and the application of fungicides. Tank mixes of demethylation-inhibiting (DMI; Fungicide Resistance Action Committee [FRAC] group 3) or quinone outside inhibitor (QoI; FRAC group 11) fungicides with chlorothalonil (FRAC group M5) at full or reduced rates were evaluated for effectiveness against A. anomala. The use of chlorothalonil in a mix with a DMI or QoI fungicide was an effective treatment for EFB even if each component of the mix was at half the labeled rate. Different liquid or dry formulations of chlorothalonil were equally effective in a tank mix for EFB control. The combination of propiconazole (FRAC group 3) tank mixed with trifloxystrobin (FRAC group 11) was not effective, whereas trees treated with propiconazole tank mixed with pyraclostrobin (FRAC group 11) resulted in significantly fewer EFB cankers compared with nontreated trees. When using tank mixes for EFB management, DMI fungicides should remain at full rates while mixing with a half-rate of chlorothalonil. In contrast, QoI fungicides and chlorothalonil could both be used at half-rates and still maintain acceptable EFB control. Tank mixing chlorothalonil with fungicides at risk of resistance development can help maintain consistent EFB control and should help prevent or delay the emergence of fungicide-resistant A. anomala isolates.

English

English

Evaluating weed control and response of newly planted peach trees to herbicides

ABSTRACTField experiments were conducted in North Carolina to determine peach response to herbicides. Mesotrione, rimsulfuron, and sulfentrazone did not injure newly planted peach trees. However, halosulfuron at the higher rate caused injury to peach trees, but did not reduce tree cross-sectional area or winter pruning weight. Another field experiment was conducted to determine the effect of herbicide-based programs on weed control. Sulfentrazone alone controlled common lamb’s-quarters and henbit but provided poor control of large crabgrass and yellow foxtail. However, a tank mix of norflurazon or oryzalin with sulfentrazone improved control of these weeds over sulfentrazone alone. Terbacil alone or in tank mix rimsulfuron, and flumioxazin alone gave excellent control of large crabgrass and yellow foxtail.