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Postemergence Weed Control in Onion with Bentazon, Flumioxazin, and Oxyfluorfen
Abstract
Field experiments were conducted in 2008 and 2010 to determine crop tolerance and weed control efficacy of the POST herbicides bentazon, flumioxazin, and oxyfluorfen applied to direct-seeded dry bulb onions on organic soil. Postemergence application of oxyfluorfen at 0.071 kg ai ha ⁻¹ resulted in less than 20% onion injury when applied at the 2 and 4 onion leaf stages and provided good control of ladysthumb and common lambsquarters. Oxyfluorfen EC caused slightly higher visual injury than oxyfluorfen SC, but there was no difference in onion yield among the treatments. Application of flumioxazin at 0.036 of 0.072 kg ai ha ⁻¹ alone or in combination with pendimethalin ACS resulted in minimal onion injury and no yield reduction. Combining flumioxazin in a tank mix with pendimethalin EC, dimethenamid-P EC, or S -metolachlor EC resulted in significant onion injury and yield reduction. Flumioxazin plus S -metolachlor, dimethenamid-P, or pendimethalin improved ladysthumb control in one of two years. Bentazon applied at 0.56 kg ai ha ⁻¹ produced moderate onion injury and did not control yellow nutsedge adequately. Bentazon applied at 1.12 kg ai ha ⁻¹ provided good control of yellow nutsedge but caused serious onion injury and yield loss.
... Eclipta (Eclipta prostrata) was better controlled by oxyfluorfen than pendimethalin (Gilreath et al., 2008), and oxyfluorfen gave the best preemergence control of weeds at a site where the most common weed was nettleleaf goosefoot (Chenopodium murale) (Qasem, 2007). Broadleaf weed control outcomes for pendimethalin, S-metolachlor, and dimethenamid-P can be improved with additional herbicides in the spray solution (Grichar, 2007;Hutchinson, 2012); however, some tank mixtures may increase risk of onion injury compared with herbicides applied alone (Herrmann et al., 2017). Oxyfluorfen and flumioxazin are broad-spectrum, diphenyl-ether herbicides that inhibit protoporphyrinogen oxidase, an enzyme that catalyzes the biosynthesis of chlorophyll and heme compounds in plants (Zhao et al., 2020). ...
... Another possible strategy for increasing seaside petunia susceptibility to foliar applications of oxyfluorfen is to apply an emulsifiable concentrate (EC) formulation of oxyfluorfen rather than the water-based suspension concentrate (SC) formulation used in our study, because a previous study determined that an EC formulation of oxyfluorfen improved control of specific broadleaf weeds when compared against a SC formulation (Herrmann et al., 2017). The EC formulation also caused more foliar injury on onions, but there was no difference in onion bulb yield between the EC and SC formulations of oxyfluorfen (Herrmann et al., 2017). ...
... Another possible strategy for increasing seaside petunia susceptibility to foliar applications of oxyfluorfen is to apply an emulsifiable concentrate (EC) formulation of oxyfluorfen rather than the water-based suspension concentrate (SC) formulation used in our study, because a previous study determined that an EC formulation of oxyfluorfen improved control of specific broadleaf weeds when compared against a SC formulation (Herrmann et al., 2017). The EC formulation also caused more foliar injury on onions, but there was no difference in onion bulb yield between the EC and SC formulations of oxyfluorfen (Herrmann et al., 2017). Seaside petunia susceptibility to flumioxazin might be enhanced by adjuvants that promote foliar retention of herbicide solutions (Nelson and Penner, 2006); however, flumioxazin labels specify that applications after onion emergence should not include adjuvants added to spray mixtures (Winfield Solutions, 2016). ...
Seaside petunia ( Calibrachoa parviflora ) is a mat-forming plant species that was recently reported in fall-seeded onion ( Allium cepa ) in the southwestern United States. To initiate development of herbicide recommendations for seaside petunia in onion, we conducted a study to determine seaside petunia susceptibility to commonly used herbicides for broadleaf weed control after onion emergence. Our study included herbicides applied at below-label rates, which provided insights on seaside petunia responses to reductions in the amount of herbicide available for plant absorption. For herbicides with preemergence activity, our growth chamber study indicated that soil applications of flumioxazin or oxyfluorfen (0.06 and 0.25 lb/acre, respectively) prevented seaside petunia seedling emergence when applied at 0.125×, 0.25×, 0.5×, and 1.0× the labeled rates for onion. Labeled rate treatments of dimethenamid-P (0.84 lb/acre) and S -metolachlor (0.64 lb/acre) inhibited seedling emergence similar to labeled rate treatments of flumioxazin and oxyfluorfen; however, below-label rate treatments of dimethenamid-P and S -metolachlor resulted in diminished control of seaside petunia compared with the labeled rate treatments. Following labeled rate applications of dimethyl tetrachloroterephthalate [DCPA (6 lb/acre)] and pendimethalin (0.71 lb/acre), more than 50% of seaside petunia seedlings emerged compared with the nontreated control. For herbicides with postemergence activity on weeds, our greenhouse study indicated that bromoxynil at 0.37 lb/acre, flumioxazin at 0.06 lb/acre, and oxyfluorfen at 0.25 lb/acre equally reduced growth of seaside petunia plants that were small at the time of spraying (stem length, 1–2 cm). Postemergence control of seaside petunia with oxyfluorfen and flumioxazin decreased as plant size at spraying increased; however, bromoxynil effects on seaside petunia remained high as stem length at spraying increased from 5 to 12 cm. Based on the results of this study, we conclude that promising herbicide programs for seaside petunia in onion include oxyfluorfen or flumioxazin for preemergence control and bromoxynil for postemergence control. These herbicides, alone and in combination, should be evaluated for seaside petunia control and onion phytotoxicity in future field trials.
... Onion farmers usually face two challenges that can hinder successful weed control. First, onion has slow initial growth and tubular leaf architecture, which results in a lower competitive ability to capture resources (Herrmann et al., 2017). Second, few herbicides are available for post-emergence applications, requiring manual weed control in many situations, which increases production costs (Herrmann et al., 2017). ...
... First, onion has slow initial growth and tubular leaf architecture, which results in a lower competitive ability to capture resources (Herrmann et al., 2017). Second, few herbicides are available for post-emergence applications, requiring manual weed control in many situations, which increases production costs (Herrmann et al., 2017). ...
Weed management is essential in vegetable crops, constituting the main production cost. Cultural control strategies can help minimize weed interference and decrease the critical period for weed control (CPWC) when well implemented. Localized nutrient and water supply may favor crop growth, suppressing weeds, and reducing the CPWC. We hypothesized that the drip system reduces the CPWC compared to the micro-sprinkler system and may be recommended as a cultural control method. To support our hypothesis, the objective was to determine the CPWC in onion cultivated under drip or micro-sprinkler during three cropping seasons. Field experiments were conducted during 2016, 2017, and 2018 to evaluate the effects of drip and micro-sprinkler irrigation had on the CPWC in onion (Allium cepa L.). The coexistence of weed in the onion lifecycle significantly reduced the bulb yield for both irrigation systems. The reduction by weed infestation in relative onion bulb yield for the drip system was 61.8, 80.9, and 97.6% in 2016, 2017, and 2018 seasons, respectively. For micro-sprinkler systems, the reduction was 89.2, 85.2, and 98.6% in the 2016, 2017, and 2018 seasons, respectively. The CPWC varied according to the irrigation system and season. For example, in a drip system, the CPWC was 11, 17, and 74 days for 2016, 2017, and 2018. In the micro-sprinkler system, the CPWC was 18, 53, and 45 days in 2016, 2017, and 2018. The predominant weed community determines the irrigation system (drip or micro-sprinkler) that promotes better cultural weed control and reduction of the CPWC in onion cropping systems.
... Second, direct seeding makes it more difficult to control weeds than transplanting because seeded onions have slow initial growth and tubular leaf architecture, which results in a lower competitive ability to capture resources (Herrmann et al. 2017). Bond and Burston (1996) showed that when weeds coexisted with onions for 35 days after emergence, the production loss reached 96%. ...
Direct seeding has become increasingly popular in an onion cultivation in the last decade, especially in Hokkaido. Although direct seeding can save time and costs of raising seedlings, onion farmers usually face three challenges. First, the germination rate of seeded onions is not good. Second, direct seeding makes it more difficult to control weeds than transplanting. Third, herbicides for weeds also cause damage to seeded small onions. It is vital to enhance the initial growth of seeded onions to solve these problems. The purpose of this study was to confirm whether drip irrigation/fertigation with a satellite system could enhance the initial growth of seeded onions and increase the yield in the actual commercial field of Hokkaido as an on-farm experiment. The results in 2021 showed that germination rate of drip fertigated plot was at 95%, while conventional cultivation plot was at 75%. We also confirmed that drip fertigation enhanced the initial growth. The yield of fertigated onions was 1.8 times greater than the yield by conventional cultivation. At the same time, we could decrease nitrogen fertilizer by 16% compared with the conventional value. Drip fertigation also increased the percentage of larger onion bulbs. The results also confirmed that the satellite image analysis was valid and useful to estimate the quantity of evapotranspiration and decide the amount of irrigation water. For these reasons, drip fertigation systems with satellite image analysis should be considered one of the best methods for direct seeding of onions.
... It is an herbicide that preferentially kills broadleaf weeds by blocking photosynthesis. Sodium Bentazone is available commercially [36,37] to control the herbaceous plants and shrubs in alfalfa, arugula, cereal grains, clover, digoxin, onions, etc. [38,39]. In vivo study on mice has confirmed that bentazone does not show any genotoxicity or impair spermatogenesis at a low dose (30 μg/L for 100 days) [20]. ...
Background: Thousands of people worldwide pass away yearly due to neurological disorders, cardiovascular illnesses, cancer, metabolic disorders, and microbial infections. Additionally, a sizable population has also been impacted by hepatotoxicity, ulcers, gastroesophageal reflux disease, and breast fissure. These ailments are likewise steadily increasing along with the increase in life expectancy. Finding innovative therapies to cure and consequently lessen the impact of these ailments is, therefore, a global concern.
Methods and materials: All provided literature on Guaiazulene (GA) and its related compounds were searched using various electronic databases such as PubMed, Google Scholar, Web of Science, Elsevier, Springer, ACS, CNKI, and books via the keywords Guaiazulene, Matricaria chamomilla, GA-related compounds, and Guaiazulene analogous.
Results: The FDA has approved the bicyclic sesquiterpene GA, commonly referred to as azulon or 1,4-dimethyl-7 isopropylazulene, as a component in cosmetic colorants. The pleiotropic health advantages of GA and related substances, especially their antioxidant and anti-inflammatory effects, attracted a lot of research. Numerous studies have found that GA can help to manage various conditions, including bacterial infections, tumors, immunomodulation, expectorants, diuretics, diaphoresis, ulcers, dermatitis, proliferation, and gastritis. These conditions all involve lipid peroxidation and inflammatory response. In this review, we have covered the biomedical applications of GA. Moreover, we also emphasize the therapeutic potential of guaiazulene derivatives in preclinical and clinical settings, along with their underlying mechanism(s).
Conclusion: GA and its related compounds exhibit therapeutic potential in several diseases. Still, it is necessary to investigate their potential in animal models for various other ailments and establish their safety profile. They might be a good candidate to advance to clinical trials.
... Since all the mentioned potential partners of fl umioxazine are applied in sunfl ower crops before the germination of this plant, this study envisages the investigation of the effectiveness of the comprehensive application of fl umioxazine when introduced into the soil before the germination of sunfl ower and the weeds. It is noteworthy that fl umioxazine is used in mixtures with other herbicides for weed control in agriculture of different countries (Hermann et al, 2017, Schutte, 2018, but there are no current data on its application in the sunfl ower crops. ...
Aim. This work is devoted to the search for potential partners for the integrated application of flumioxazine in sunflower crops. This herbicide is an inhibitor of protoporphyrinogen oxidase (PPO) in weed plants. The resistance to this class of herbicides is not yet common today, compared to other classes. Therefore, the work is aimed at de- veloping flumioxazine-based herbicide compositions that effectively prevent the emergence of herbicide-resistant weed biotypes. Methods. The interaction effects, weed control efficiency, and crop selectivity were studied when flumioxazine was used in the mixtures with herbicides acetochlor and propisochlor (long-chain fatty acid synthesis (LCFAS) inhibitors), promethrin (electron transport (ET) inhibitor in photosystem 2 (PS 2) of chloroplasts) and fluorochloridone (inhibitor of carotenoid synthesis by blocking the activity of phytoendesaturases (PDS)) both in the experiments on sunflower crops and in greenhouse experiments using the model objects. Results. The studies have shown that when flumioxazine is applied with the ET inhibitor, promethrin, the interaction is antagonistic, resulting in poor weed control efficiency and sunflower yield decrease. The tank mixtures of flumioxazine with LCFAS inhibitors acetochlor and propisochlor provide high weed control efficiency but are low in selectivity for sunflowers. The interaction between flumioxazine and fluorochloridone within the recommended application rates is additive. The tank mixture of flumioxazine and fluorochloridone herbicides at the application rates of 55 and 500 g/ha, respectively, is selective for sunflowers. In terms of control efficiency of annual dicotyledons, this mixture of herbicides exceeded, and in terms of control efficiency of annual cereal weed species was only slightly inferior to the control integrated herbicide (metolachlor + terbuthylazine). In these application rates, flumioxazine and fluo- rochloridone provided sunflower yield on par with this complex herbicide. Сonclusions. Among the investigated herbicides, the optimal partner of flumioxazine for complex use in sunflower crops was the herbicide, inhibitor PDS, fluorochloridone. Given that flumioxazine and fluorochloridone differ in their phytotoxicity mechanisms but share a common spectrum of controlled weed species, the use of a mixture of these herbicides is a factor that minimizes the likelihood of the emergence of herbicide-resistant weed biotypes.
... In previous studies, some of these herbicides were found to be effective on other sedge species. For example, bentazon applied at 1120 g ha −1 provided 95% to 100% control of yellow nutsedge [16]. Similarly, imazapic (an imidazolinone herbicide) has been reported to provide effective control of annual sedge (Cyperus compressus L.), cylindric sedge (Cyperus retrorsus Chapm.), and globe sedge (Cyperus globulosus Aubl.) [17]. ...
Navua sedge is a difficult-to-control perennial sedge in north Australian farming systems, including fallow fields, pastures, and along roadsides and fencelines. A set of pot trials were conducted to evaluate the performance of different herbicides when used alone or in mixtures on different sizes of Navua sedge plants, and the performance of different adjuvant treatments on the rainfastness of halosulfuron-methyl. Glyphosate at 1080 g·ha−1, halosulforon-methyl at 49 g·ha−1, and paraquat at 600 g·ha−1 provided complete control of Navua sedge at the 6-leaf stage. Azimsulfuron at 20 g·ha−1 resulted in 18% and 39% survival of the 14 to 18 leaf stage and 60–70 leaf stage plants, respectively. Compared with the nontreated, this herbicide treatment suppressed plant biomass by 99.6% and 93%, respectively, and the surviving plants did not produce seed heads. A sole application of azimsulfuron, glyphosate, or halosulfuron-methyl was not effective on very large plants (140–150 leaf stage; 40–42 cm tall) of Navua sedge. However, a mixture of any two herbicides resulted in the complete control of Navua sedge. Compared with the currently used adjuvants at 0.5 to 1% concentrations, the use of non-ionic adjuvants at high concentrations (i.e., 2% ActivatorTM, HastenTM, and UptakeTM) improved the rainfastness of halosulfuron-methy when applied at 49 g·ha−1 on Navua sedge. This study identified effective herbicide treatments (e.g., azimsulfuron-based combinations) for the management of large plants of Navua sedge.
... Bentazone [3-Isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] was initially registered in 1975. It has been used for selective POST control of broadleaf weeds and sedges in alfalfa, asparagus, cereals, clover, digitalis, dry peas, flax, garlic, grass, green lime beans, mint, onions, potatoes, snap beans for seeds, sorghum, soybeans, and sugarcane [20][21][22][23]. Bentazone is a contact herbicide that interferes with susceptible plants' ability to use sunlight in producing survival energy through photosynthesis. ...
Soybean is one of the most important crops widely used as food, feed, and industrial products. Weeds compete with the crops for light, nutrients, water, space, and other growth requirements, causing an average yield reduction of 37% in soybean. Bentazone is an herbicide that selectively kills broadleaf weeds by inhibiting photosynthesis. It is widespread in soybean-cultivating areas including genetically modified organism (GMO) and GMO-free regions all around the world. This herbicide carries a double-edged sword since it can also incur damage to crops upon application. The challenge, therefore, lies in the deliberate selection of bentazone-tolerant cultivars. We systematically analyzed several factors that affect the metabolism of bentazone in soybean, such as phenotypic and genotypic differences among soybean accessions, the time and method of application, the absorption and metabolism of bentazone in soybean, and the effects of effective application and cultivar selection on yield and crop injury. Furthermore, we recommend that further studies should be done in aid of discovering more tolerant soybean cultivars. We hope that our review will help farmers and soybean producers, as well as geneticists, in developing bentazone-tolerant soybean cultivars to improve the global yield of soybean crops as a response to the ever-dynamic food demand across the globe.
... In line with our results, chemical control of onion weeds with oxyfluorfen or oxadiazone were competitive effective compared with hand-weeding (Mc Intyre, and Barbe, 1995). In addition, post emergence application of bentazon and oxyfluorfen in onion (Herrmann et al., 2017;Shimi and Maillet, 1998;Maknali, and In each column and for each experimental factor means with the same letters or means with differences less than LSD do not have statistically significant differences at 5% level of probability. PPI, pre plant soil incorporated; PREA, pre emergence application; POEA, post emergence application. ...
Allium hirtifolium Boiss (Persian shallot), called “Mooseer” in Persian, as a medical and industrial species, is poor competitor against weeds. Due to high pressure on its natural habitats by harvesting for food and medicinal consumption, it is necessary to domesticate it for commercial production. There is rare information on the tolerance of A. hirtifolium to herbicide applications. In present study, the effects of 19 weed control scenario along with two weedy and weed free controls on the weeds control and yield response of A. hirtifolium were evaluated. The field experiment was conducted in two years (Autumn 2015 to Summer 2017), as randomized complete block design with three replicates. Flixweed (Descurainia sophia L.) was the dominant weed in the experimental plots in both years. Hand-weeding caused complete weed removal and resulted in the highest crop yield. Oxyfluorfen herbicide caused the highest crop phytotoxicity in both rates (180+180 and 360 g a.i. ha⁻¹). Whereas, bentazone and oxyfluorfen produced the highest crop yield. Based on our finding, although hand-weeding had highest crop yield, post emergence application of bentazone (1200 and 1440 g a.i. ha⁻¹), oxadiazone (360 g a.i. ha⁻¹) and oxyfluorfen (360 g a.i. ha⁻¹) can be suitable options for selective chemical weeds control in A. hirtifolium, due to gained acceptable yield by providing satisfactory levels of weed control and crop phytotoxicity.
... However, the improper use of some pesticides in the onion crop may still cause health risks from onion consumption. Several studies have been carried out to investigate the degradation behavior, residue distribution, and dietary risk of different pesticides, including insecticides (17,192), fungicides (193)(194)(195), and herbicides (196), which were used for pest and disease protection and weed control in onion planting. Overall, the dietary risk of these pesticides through onion could be negligible with the reasonable usage does of pesticides and enough preharvest interval ( Table 2). ...
Onion (Allium cepa L.) is a common vegetable, widely consumed all over the world. Onion contains diverse phytochemicals, including organosulfur compounds, phenolic compounds, polysaccharides, and saponins. The phenolic and sulfur-containing compounds, including onionin A, cysteine sulfoxides, quercetin, and quercetin glucosides, are the major bioactive constituents of onion. Accumulated studies have revealed that onion and its bioactive compounds possess various health functions, such as antioxidant, antimicrobial, anti-inflammatory, anti-obesity, anti-diabetic, anticancer, cardiovascular protective, neuroprotective, hepatorenal protective, respiratory protective, digestive system protective, reproductive protective, and immunomodulatory properties. Herein, the main bioactive compounds in onion are summarized, followed by intensively discussing its major health functions as well as relevant molecular mechanisms. Moreover, the potential safety concerns about onion contamination and the ways to mitigate these issues are also discussed. We hope that this paper can attract broader attention to onion and its bioactive compounds, which are promising ingredients in the development of functional foods and nutraceuticals for preventing and managing certain chronic diseases.
... Bentazone [3-Isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] was initially registered in 1975. It has been used for selective POST control of broadleaf weeds and sedges in alfalfa, asparagus, cereals, clover, digitalis, dry peas, flax, garlic, grass, green lime beans, mint, onions, potatoes, snap beans for seeds, sorghum, soybeans, and sugarcane [20][21][22][23]. Bentazone is a contact herbicide that interferes with susceptible plants' ability to use sunlight in producing survival energy through photosynthesis. ...
Soybean is one of the most important crops widely used as food, feed, and industrial products. Weeds compete with the crops for light, nutrients, water, space, and other growth requirements, causing an average yield reduction of 37% in soybean. Bentazone is an herbicide that selectively kills broadleaf weeds by inhibiting photosynthesis. It is widespread in soybean-cultivating areas including genetically modified organism (GMO) and GMO-free regions all around the world. This herbicide carries a double-edged sword since it can also incur damage to crops upon application. The challenge, therefore, lies in the deliberate selection of bentazone-tolerant cultivars. We systematically analyzed several factors that affect the metabolism of bentazone in soybean, such as phenotypic and genotypic differences among soybean accessions, the time and method of application, the absorption and metabolism of bentazone in soybean, and the effects of effective application and cultivar selection on yield and crop injury. Furthermore, we recommend that further studies should be done in aid of discovering more tolerant soybean cultivars. We hope that our review will help farmers and soybean producers, as well as geneticists, in developing bentazone-tolerant soybean cultivars to improve the global yield of soybean crops as a response to the ever-dynamic food demand across the globe.
... This inhibition of photosynthesis and oxidative stress is followed by cell damage (Dat et al., 1998;Han and Wang, 2002). In agreement with previous reports (Diebold et al., 2004;Herrmann et al., 2017;Lima et al., 2018), our results indicated the bentazon could interfere with Under stress conditions, plants usually generate higher levels of ROS, which subsequently induce peroxidation of membrane lipids and oxidative damage (Kar, 2011;Munn e-Bosch and Peñuelas, 2003). Melatonin is a plant growth regulator that improves photosynthetic efficiency in higher plants under stressful conditions (Jiang et al., 2016;Yin et al., 2013;Zhao et al., 2015). ...
Weed competition is a main factor limiting sweetpotato [ Ipomoea batatas (L.) Lam] production. Yellow nutsedge ( Cyperus esculentus L.) is a problematic weed to control due to its ability to quickly infest a field and generate high numbers of tubes and shoots. Compounding this is the lack of a registered herbicide for selective postemergence control of yellow nutsedge. Research was conducted to evaluate the bentazon dose response of two sweetpotato cultivars and one advanced clone and to evaluate the plant hormone melatonin to determine its ability to safen bentazon post emergence. Bioassays using Murashige and Skoog (MS) media supplemented with melatonin (0.232 g a.i./L and 0.023 g a.i./L) and bentazon (0.24 g a.i./L) were conducted to evaluate the effect of bentazon on sweetpotato and to determine the interactive response of the Beauregard cultivar to bentazon and exogenous applications of melatonin. Beauregard swas the most tolerant cultivar and required dosages of bentazon that were two-times higher to cause the same injury compared with other cultivars. MS media containing melatonin and bentazon showed fewer injuries and higher plant mass than plants treated with bentazon alone. These results indicate that sweetpotato injury caused by bentazon may be reduced by melatonin.
Journal of Crop Production and Processing
Isfahan University of Technology.
In order to evaluate the effect of different planting seedbeds (stale and false) and application of Oxyfluorfen herbicide on yield, yield components and control of garlic weeds, a split-plot experiment was conducted based on a randomized complete block design (RCBD) with three replications in the cropping year 2020-2021 at Agricultural Sciences and Natural Resources University of Khuzestan. The main plot consisted of different planting seedbeds: Conventional seedbed (without irrigation using plow and disc); stale seedbed (using Paraquat herbicide); stale seedbed (using Glyphosate herbicide); false seedbed (using flame application) and false seedbed (with manual cultivation). Different dosages of Oxyfluorfen herbicide (0, 1, 1.5 and 2 L/ha as split dosage) were considered as subplots. The highest total dry weight of weeds (231 g/m2) was observed in the presence of conventional seedbed treatment and non-application of herbicide. The lowest dry weight of weeds was observed in the presence of stale seedbed with glyphosate and application of 2 L/ha of Oxyfluorfen herbicide. The highest bulb yield of garlic (580 g/m2) was achieved in the presence of glyphosate seedbeds with application of herbicide at 1.5 L/ha and the lowest bulb yield (91.2 g/m2) was observed in the presence of conventional seedbed and non-application of herbicide. In conclusion, application of 2 L/ha herbicide in split doses was recommended.
Due to excessive crop damage, currently, there are no selective postemergent (POST) herbicides registered for sweetpotato [Ipomoea batatas (L.) Lam] to control broadleaves and nutsedge species. Expansion of bentazon and mesotrione herbicide labels to include sweetpotato would be beneficial for growers. Two experiments were conducted. The first evaluated the dose response of sweetpotato cultivars Beauregard and Covington to bentazon (514, 1,028, and 1,542, g a.i. ha–1) and mesotrione (105, 210, and 315 g a.i. ha–1) when melatonin, 24‐epibrassinolide, or ascorbic acid (AsA) were included in the tank mix. The second experiment evaluated the efficiency of bentazon and mesotrione for control of yellow nutsedge (Cyperus esculentus L.) and Palmer amaranth (Amaranthus palmeri S. Wats.), when different doses of melatonin, 24‐epibrassinolide, or AsA were added to each herbicide. In the first experiment, when treated with herbicide alone, Beauregard exhibited injury levels lower than Covington for both herbicides. No injury was observed when plants were treated with plant hormones or AsA alone. At the lowest dose of bentazon and mesotrione, the addition of AsA or plant hormones in the tank mix significantly reduced percentage injury and increased plant tolerance, requiring higher doses of herbicide to cause 10, 20, and 30% injury. In the second experiment, the addition of plant hormones and AsA in the tank mix had no antagonistic effect on herbicide effectiveness, exhibiting similar levels of injuries as herbicides application alone. These results suggest that the use of plant hormones and AsA could improve sweetpotato tolerance to POST applications of bentazon and mesotrione without reducing herbicide effectiveness.
Introduction: Onion (Allium cepa L.) is one of the most important vegetables (with 2.305 million tons production) in Iran. Onion cultivation area of southern Kerman is 5732 hectares and this region is ranked first for onion production (307 thousand tons of production) in Iran. Onion growth and yield are significantly reduced by weed competition. Among the dominant weeds in onion fields at southern Kerman, Cyperus rotundus is one of the most important and problematic weeds. The slow growth of onion in the early stage, causes a significant yield loss due to the competition. C. rotundus is a perennial weed of the Cyperaceae family spreading quickly throughout the extensive underground system and tuber, with high ability to compete. This weed can decrease the average onions yield by 23 – 84%. Application of herbicides is the most prevalent weed control method in onion fields. Oxyfluorfen, and haloxyfop-r-methyl ester, are the commonly used herbicides for C. rotundus control in onion fields at southern Kerman. Therefore, the objective of this study was to investigate the effects of different herbicides on this weed.
Materials and Methods: This experiment was conducted in Agricultural and Natural Resources research and Education Center, Jiroft, southern Kerman, during 2017-2018 and 2018-19. The experiment was carried out in randomized complete block design with three replications. The experiment treatments included: T1- Metribuzin (Sencor) 80% WP 500 gr.ha-1, T2- Oxyfluorfen(goal) EC24%, 2 lit.ha-1, T3- Oxadiazon (ronstar) EC 12% 3 lit.ha-1 + Oxyfluorfen(goal) EC24%, 2 lit.ha-1, T4- Pendimethalin (stomp) EC33% ,3 lit.ha-1, T5 Oxadiazon (ronstar) EC 12% 3 lit.ha-1, T6- Oxadiazon (ronstar) EC 12% 3 lit.ha-1 + Bentazon (bazageran) SL48% 3 lit.ha-1, T7- Oxyfluorfen(goal) EC24% at 1/5 lit.ha-1 two stages by 0.75 lit.ha-1, (one week after transplanting and three weeks afterwards), T8- Pendimethalin (prowl) CS 45.5% 3 lit.ha-1, T9- hand weeding and T10- control (no control). Other weeds except C. rotundus were hand-removed during the season. The herbicides were applied using a Matabi sprayer with delivering 354 L ha-1 at 2 bar spray pressure. C. rotundus shoot and underground organs dry weight, density, average of bulb weight and onion yield were measured. Statistical analysis was carried out using SAS ver.9.1 software and the comparison of means was undertaken based on the LSD test.
Results and Discussion: The combined analysis of variance showed that the effect of treatment was significant on shoot and underground organs dry weight and density of C. rotundus, mean onion weight of bulb and yield, and reduced dry weight and density of C. rotundus and increased the onion yield. Among the chemical treatments, the combined application of Oxadiazon (Ronstar) as pre emergence followed by application of Bentazon (Bazageran) as post emergence (Treatment 6), decreased the density, underground and shoot dry weight of C. rotundus by 96.89 and 93% relative to the control, respectively. The highest onion yield was obtained from the mentioned treatment and increased the onion yield by 87% with respect to the control.
Indeed, the combined application of these two herbicides in different growth stages of weeds and onion, was able to resolve the limitations of separate application of these herbicides leading to the most effective control of C. rotundus.
Conclusion: The results of this experiment show that the combination of herbicides can be an effective strategy to increase their effectiveness. The combined application of Oxadiazon (Ronstar) EC 12% at 3 lit.ha-1 as pre emergence + Bentazon (Bazageran) SL48% at 3 lit.ha-1 as post emergence was the most effective treatment after hand-weeding on purple nutsedge management and increasing the onion yield. Therefore, the mentioned treatment is recommended to control of C. rotundus in transplanting cultivation of onion in autumn farming in south of Kerman Provence.
Field studies were conducted near Oakes, Absaraka, and Carrington, North Dakota to determine if bromoxynil and oxyfluorfen applied post-emergence at reduced doses and spray volumes to one-leaf onion would provide effective early-season broadleaved weed control without significant crop injury. Oxyfluorfen generally provided more effective early-season broadleaved weed control than bromoxynil when applied at reduced spray volumes and doses. Onion injury 1 week after treatment (WAT) was more severe with oxyfluorfen than bromoxynil applied post-emergence, but was not visible 3 WAT. Large-grade and total onion yields at Absaraka, where broadleaved weed pressure was the least, were similar in all treatments except the untreated check. At Carrington and Oakes, where broadleaved weed pressure was much greater, no treatments had large-grade or total onion yields similar to the hand-weeded check. However, large-grade and total yields from onion treated with reduced doses of bromoxynil or oxyfluorfen, regardless of the spray volume, were similar to those treated with almost a four-fold increase in herbicide dose, suggesting that a reduced bromoxynil or oxyfluorfen dose at lower spray volumes to one-leaf onion may provide sufficient early-season Chenopodium album and Amaranthus retroflexus control so that post-emergence applications of bromoxynil plus oxyfluorfen to larger onion provide more effective broadleaved weed control.
Volunteer potato is highly competitive with onion and few control tactics are effective for removing this weed from an onion crop. Both volunteer potato density and duration of interference reduce onion yield, but the interaction of these factors is unknown. Field trials were conducted in 2003 in Idaho, Oregon, and Washington to determine the influence of volunteer potato density on the critical time of weed removal (CTWR) in onion. Yield losses of 2.5, 5.0, and 10% were estimated to occur at 534, 654, and 830 growing degree days (GDD) after onion emergence, respectively, with a volunteer potato density of 0.5 plants/m2. At 2.0 volunteer potato plants/m2, yield losses of 2.5, 5.0, and 10% were estimated to occur at 388, 481, and 598 GDD after onion emergence, respectively. Volunteer potato at 2.0 plants/m2 had to be removed at least one onion leaf stage sooner, compared to a weed density of 0.5 plants/m2, to avoid yield loss. Yield loss due to volunteer potato density or duration of interference was greatest among jumbo, colossal, and supercolossal market grades (P # 0.1). Lowering potato tuber density in crops preceding onion will extend the critical time for weed removal and reduce the risk of crop loss. Nomenclature: Volunteer potato, Solanum tuberosum L. 'Russet Burbank' and 'Ranger Russet'; Onion, Allium cepa L. 'Pinnacle' and 'Vaquero'.
Volunteer potatoes are difficult to control in onions and can greatly reduce onion growth and yield. Herbicides and cultivation were evaluated for control of simulated volunteer potatoes in onions in 1996 and 2000. Three interrow cultivations did not control potatoes in the onion row and the remaining plants reduced onion yield 50 and 73% compared with the hand-weeded checks. Three applications of oxyfluorfen (0.2 + 0.17 + 0.17 kg ai/ha) or bromoxynil plus oxyfluorfen (0.2 + 0.17 kg ai/ha) at the two-, three-, and four- to five-leaf stages of onions followed by a cultivation after each application reduced potato tuber weight 69 to 96% and tuber number 32 to 86% compared with cultivation alone and prevented onion yield loss associated with potatoes. Ethofumesate applied preemergence at 0.6 kg/ha followed by postemergence ethofumesate plus bromoxynil and cultivation reduced potato tuber weight 90% and tuber number 68% compared with cultivation alone, and onions yielded equal to hand-weeded checks. Two applications of fluroxypyr (0.3 kg ai/ha) plus bromoxynil (0.2 kg ai/ha) at the two- and three-leaf stages of onions followed by a cultivation after each application reduced potato tuber weight by greater than 90%, but onion yields were reduced 38 to 66%. Nomenclature: Bromoxynil; ethofumesate; fluroxypyr; oxyfluorfen; onion, Allium cepa L. ‘Fiesta’ and ‘Asgrow EX15120’; potato, Solanum tuberosum L. ‘Russet Burbank’. Additional index words: Groundkeepers (volunteer potato), tillage. Abbreviations: POST, postemergence; PRE, preemergence.
Several herbicides were sprayed on emerged London rocket ( Sisymbrium irio L.), common sunflower ( Helianthus annuus L.), ragweed parthenium ( Parthenium hysterophorus L.), annual sowthistle ( Sonchus oleraceus L.), and onion ( Allium cepa L. ‘yellow granex PRR’), to determine selectivity. Onion yields were reduced with common sunflower and London rocket interference within 7 weeks after emergence. Oxadiazon [2- tert -butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-δ ² -1,3,4-oxadiazolin-5-one] at 2.2 kg/ha controlled all but common sunflower under most field conditions and reduced the yield of onion in one experiment out of six. Methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] and bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) reduced the yields of onion in two of four experiments and three of six experiments, respectively. Both herbicides controlled most weed species, but only bromoxynil controlled annual sunflower adequately. Onion was injured when low temperature, low light intensity, and high relative humidity occurred within 3 days of the application of herbicides. Bioassays showed that oxadiazon persisted 5 months in soil in three of five experiments. Seeded London rocket populations reduced the growth of onion 20% within the first 4 weeks and 65% within 12 weeks after planting.
The effectiveness of oxyfluorfen and bromoxynil for Russian thistle control in onion was measured in a 2-yr study conducted in the high desert region of southern California. Oxyfluorfen, bromoxynil, or combinations of the two applied one at the 2-leaf growth stage of onion did not control Russian thistle. When a first application was followed 14 days later with a second herbicide application, a first application of oxyfluorfen plus bromoxynil was most effective. Oxyfluorfen applied alone as a second application was least effective, but bromoxynil alone plus oxyfluorfen improved control. Adding petroleum oil to oxyfluorfen plus bromoxynil improved Russian thistle control.
Studies were conducted to evaluate preplant incorporated (PPI), preemergence (PRE), and postemergence (POE) herbicide treatments on yellow nutsedge control and on growth and yield of transplanted onions. Most effective yellow nutsedge control (≥80%) was achieved with metolachlor applied PPI plus PRE. Metolachlor and SAN 582H were more effective applied PPI than PRE. Bentazon alone applied POE adequately controlled yellow nutsedge only 1 of 2 yr. Highest onion yields and percent jumbo bulbs were produced when treatments included metolachlor applied PPI.
The question of when to control weeds traditionally has been approached with the calculation of critical periods (CP) based on crop yields. The concept of economic critical period (ECP) and early (EEPT) and late (LEFT) economic period thresholds are presented as a comprehensive approach to answer the same question based on economic losses and costs of control. ECP is defined as the period when the benefit of controlling weeds is greater than its cost. EEPT and LEFT are the limits of the ECP and can be used to determine when first and last weed control measures should be performed. Calculation of EEPT accounts for the economic losses due to weed competition that occur between planting and postemergence weed control. In this way it is possible to better evaluate the economic feasibility of using preplant or preemergence control tactics. The EEPT for DCPA application is analyzed in the context of onion production in Colorado. The EEPT for DCPA application was calculated from an empirical regression model that assessed the impact of weed load and time of weed removal on onion yields. The EEPT was affected by control efficacy, weed-free yield, DCPA cost, and onion price. DCPA application was economically advisable in only one of 20 fields analyzed because of the tow DCPA efficacy (60%).
The competitiveness of annual weeds in irrigated sweet Spanish onions ( Allium cepa L.) was studied at North Platte, Nebraska, during 1969 and 1970. Weeds allowed to grow in the row for 2, 4, 6, and 8 weeks after onion emergence reduced onion yields 20, 20, 40, and 65%, respectively. When plots were kept weed-free until onion emergence and 2, 4, 6, 8, 10, and 12 weeks after emergence, onion yields were reduced 100, 99, 87, 75, 46, 25, and 5%, respectively. Redroot pigweed ( Amaranthus retroflexus L.), kochia ( Kochia scoparia L.), and grass weeds accounted for 54, 21, and 21%, respectively, of the total weed yield.
The effect of pre- or post-planting application of selected herbicides on growth and yield of transplanted onion and weeds was investigated in two field experiments conducted in Jordan during the 1997/1998 growing season. Weed competition throughout the season reduced onion yield by 94% and lowered onion quality. All herbicides [except metribuzin and diphenamid under rain-fed conditions, and linuron + terbutryn (Tempo®) under irrigation] increased onion growth and yield over the weed-infested control. Post-planting application of oxyfluorfen (at 2 l ha-1) at the three-to-four leaf stage resulted in better onion bulb yield than in the hand-weeded, weed-free control at both locations. Pre-planting treatment with oxyfluorfen at 2.5 l ha -1 gave higher yields than the weed-free control in irrigated onion, but not under rain-fed conditions. Oxadiazon (at 4 l ha-1) gave higher yields than in weed-free onion as a post-planting treatment under rain-fed conditions, and was second to oxyfluorfen for bulb production. Pre-planting application of pendimethalin (at 4 l ha-1) was also effective, and increased onion yields compared to weed-infested onion plots or other herbicides used under irrigation. Of all herbicides tested under Jordanian conditions, oxyfluorfen and oxadiazon were the best for yield and weed control in onion, followed by pendimethalin, methabenzthiazuron and linuron as pre-planting treatments, and pendimethalin, linuron and paraquat as post-planting applications.
Hand-weeding experiments were made over a 5 year period to determine the optimum time for weed removal in salad onions sown at different times of the year. Weed that remained from sowing until harvest, reduced onion fresh weight by up to 96% compared with the weed-free controls. In experiments made in the first 2 years, yield data from onion plots left weedy or kept weed-free for different periods indicated that a single, carefully timed weeding could be sufficient to prevent crop losses. However, the optimum weeding time varied from 21 to 56 days after 50% crop emergence. In subsequent experiments with salad onions sown on four different dates in each of 3 years, single and multiple weedings made within the defined optimum period did not consistently prevent crop losses.
Experiments were conducted for two consecutive seasons to evaluate the efficacy of herbicides for control of broadleaved weeds which were applied only once in irrigated onion. Oxyfluorfen and oxadiazon were used both pre- and post-emergence, metribuzin only pre-emergence, and bentazon only post-emergence. Hand-weeded and weedy checks were included. Visual ratings estimated 65 days after crop emergence indicated that weed control was adequate in oxyfluorfen and oxadiazon treatments, but the onion plants were damaged, particularly in oxyfluorfen-treated plots. Onion bulb yields were higher in hand-weeded plots than in any other treatment. The results demonstrated the inadequacy of single herbicide applications to provide season-long broadleaved weed control and adequate onion dry bulb yield. Results provide evidence that the critical period for weed control in onion is extended beyond the first few weeks after crop emergence.
The process of labeling new herbicides for specialty crops has always been difficult. Progress in solving specialty crop weed control problems will likely be more challenging in the future. Major crops like corn, cotton, rice, soybean, and wheat are planted on millions of hectares, and most of these crops are treated with herbicides. In contrast, specialty crops (i.e., minor crops, e.g., container ornamentals or lettuce) are planted on 122,000 ha or less; thus, the potential value of herbicide sales is limited in these crops by the low number of hectares planted per crop. High crop value, small hectarage per crop, and generally marginal herbicide selectivity results in a high potential of liability for herbicide registrants and little incentive to label herbicides in these crops. The Interregional Project Number 4 (IR-4) program facilitates the registrations of pesticides on minor crops. Work needed to support pesticide tolerance in a given crop is conducted by IR-4 and cooperators. However, to develop new crop tolerances, the IR-4 process requires new herbicides. The success of glyphosate-resistant soybean has resulted in a less profitable herbicide market for all crops. In response, most primary pesticide manufacturers have reduced the size, or even eliminated herbicide discovery programs. As private industry slows or stops herbicide development, there will be fewer new minor-crop herbicides. Many questions face minor-crop weed scientists. For example, what are other practical solutions to control weeds in minor crops besides herbicides? Should research focus on development of competition models and decision thresholds or on weed removal tools such as robotics? What funding sources are available for minor-crop weed scientists? Are grant programs at the Federal level prepared to increase support for minor-crop weed research? Will university administrators replace retiring specialty crop weed scientists, knowing that their funding sources will produce little overhead? These questions require a response from all parties interested in specialty crop weed control. Nomenclature: Corn, Zea mays L., cotton, Gossypium hirsutum L., lettuce, Lactuca sativa L., rice, Oryza sativa L., soybean, Glycine max (L.) Merr.; wheat, Triticum aestivum L.
Field experiments were conducted in 2004 and 2005 to determine the tolerance of direct-seeded green onion to selected herbicides applied before or after green onion emergence. Preemergence herbicides included S-metolachlor, pendimethalin, dimethenamid, quinclorac, pronamide, ethofumesate, and DCPA, a registered standard. Herbicide applied to two- to three-leaf green onion included glyphosate, trifloxysulfuron, flumioxazin, phenmedipham, ethalfluralin, pendimethalin, S-metolachlor, and oxyfluorfen. Plots were cultivated and hand weeded to minimize negative effects of weed interference on the crop. All herbicides applied at seeding, excluding DCPA, caused excessive injury (>25%) to green onion in at least 1 of 2 years. Oxyfluorfen, ethalfluralin, or S-metolachlor applied after crop emergence caused less than 10% injury in both years to green onion. Green onion yields following treatment with oxyfluorfen, ethalfluralin, or S-metolachlor were equivalent to the nontreated control. All other herbicides applied after crop emergence resulted in height, density, or yield reductions relative to a nontreated control in at least 1 of 2 years. Nomenclature: DCPA, dimethenamid, ethalfluralin, ethofumesate, flumioxazin, glyphosate, oxyfluorfen, pendimethalin, phenmedipham, pronamide, quinclorac, S-metolachlor, trifloxysulfuron, green onion, Allium cepa L. ‘White Spear 85’
The activity of emulsifiable concentrate (EC) formulation of pendimethalin was studied using a petri dish bioassay based on root response of corn, oat, sorghum, and sugar beet grown in soil. Furthermore, the oat bioassay was used to determine the activity of EC, microencapsulated (ME), and water-dispersible granule (WDG) formulations of pendimethalin. Also, field persistence in soil of these pendimethalin formulations was studied with petri dish and pot bioassays, based on root response of oat and sugar beet. All bioassays indicated that activity of all pendimethalin formulations was increased with increasing herbicide concentration. In silty clay loam soil, oat and sugar beet exhibited the highest sensitivity to EC-pendimethalin concentrations and corn the lowest; sorghum showed intermediate herbicide sensitivity. EC of pendimethalin showed the highest activity on oat and ME pendimethalin the lowest; WDG-pendimethalin showed similar activity to that of ME pendimethalin. Field persistence was significantly increased with increasing rate of application, but it was slightly increased by the ME formulation. Nomenclature: Pendimethalin; corn, Zea mays L. ‘Pioneer Costanza’; oat, Avena sativa L. ‘Kassandra’; sorghum, Sorghum bicolor L. ‘5515’; sugar beet, Beta vulgaris L. ‘Bianca’. Additional index words: Microencapsulated formulation, pendimethalin. Abbreviations: DAT, days after treatment; EC, emulsifiable concentrate; GI10, days after treatment for 10% oat root growth inhibition; GR50, herbicide concentration required to give 50% inhibition of plant indicator root growth; ME, microencapsulated; PRE, preemergence; WDG, water-dispersible granule.
Weed removal experiments were conducted in growers' fields in northern Colorado to assess the effect of duration of competition, weed density, weed competitiveness and crop density on irrigated seeded onion (Allium cepa L.). Duration of competition, expressed in thermal time units (TTUs) with a base of 7.2^C, explained 65% of the variation in the reduction of onion relative yield. The first significant reduction in onion relative yield was at 90 TTUs, averaged over weed load (weed density adjusted by competitiveness) and onion density. A polynomial multiple regression model, accounting for duration of competition and weed load, explained 75% of the variation in onion relative yield. A non-linear multiple regression model, combining a gamma function response of relative yield to duration of competition plus a hyperbolic response of relative yield to weed load, was as good a predictor and a better description of the system. Onion relative yield was more sensitive to the duration of weed competition than to weed load. Bulb size class distribution and the resulting average onion price were affected by weed competition. Polynomial models were used to describe changes in bulb size class proportions as a function of duration of competition, weed load and onion density.
Dry bulb onion tolerance to sequential applications of bentazon applied to control yellow nutsedge (Cyperus esculentus L.) in the Pacific Northwest
- Epeachey
- Raboydston Jfelix
Onions: Commercial Vegetable Recommendations
- Bhzandstra
- Ejgrafius
- Ddwarncke Mllacy
Yellow nutsedge (Cyperus esculentus) management in transplanted onions (Allium cepa)
- Jwkeeling
- Jrabernathy Dabender
Volunteer potato (Solanum tuberosum) control with herbicides and cultivation in onion (Allium cepa)
- Mdseymour Raboydston
Multiple applications of reduced-rate herbicides for weed control in onion
- Hmhatterman-Valenti Jrloken
Timing the removal of weeds from drilled salad onions to prevent crop losses
- Sburston Wbond
Modelling the effect of duration of weed competition, weed density and weed competitiveness on seeded, irrigated onion
- Cmdunan
- Pwestra
- Eeschweizer
- Fdmoore Dwlybecker
The challenges of specialty crop weed control, future directions
- Djdoohan Safennimore
Tolerance of direct-seeded green onions to herbicides applied before or after crop emergence
- Jknorsworthy
- Cmeister Jpsmith
Goaltender® herbicide label
- Anonymous
Dry bulb onion tolerance to sequential applications of bentazon applied to control yellow nutsedge (Cyperus esculentus L.) in the Pacific Northwest
- Peachey