Bentazon Postemergence Research Articles

Control of acetolactate synthase-inhibiting herbicide-resistant Palmer amaranth (Amaranthus palmeri) with sequential applications of dimethenamid-Pin dry edible bean

AbstractBiotypes of Palmer amaranth that are resistant to acetolactate synthase (ALS) inhibitor are becoming widespread in western Nebraska. There are limited effective postemergence (POST) herbicides labeled for ALS-inhibitor-resistant Palmer amaranth control in dry edible bean. The objective of this study was to evaluate the efficacy of dimethenamid-Pin a sequential preemergence (PRE) fb followed by (fb) POST program at two POST application timings, the first and third trifoliate stages (V1 and V3, respectively), for controlling ALS-inhibitor-resistant Palmer amaranth in dry edible bean. A field study was conducted in 2019, 2020, and 2021 in Scottsbluff, NE. PRE-alone applications of pendimethalin + dimethenamid-Pprovided inconsistent Palmer amaranth control. Dimethenamid-Papplied POST following a PRE application of pendimethalin + dimethenamid-Pprovided effective (>90%) Palmer amaranth control at 4 wk after V3 only at the V1 application timing in 2019. In 2020 and 2021 dimethenamid-Papplied POST at V1 and V3 following a PRE application of pendimethalin + dimethenamid-Pprovided 99% and 98% Palmer amaranth control at 4 wk after V3, and 98% and 94% Palmer amaranth control at harvest, respectively. Palmer amaranth biomass was reduced by 95% to 99% and by 96% to 98% compared with the -nontreated control when dimethenamid-Pwas applied POST at V1 and V3, respectively, following a PRE application of pendimethalin + dimethenamid-Pin 2020 and 2021. Application of a mixture of dimethenamid-Pwith imazamox + bentazon POST provided similar results to those of the fomesafen-containing treatments and dimethenamid-Palone POST. Dimethenamid-Papplied POST following a PRE application of pendimethalin + dimethenamid-Presulted in similar yield as the fomesafen-containing treatments. If fomesafen is not an option due to the crop rotation interval restriction, using dimethenamid-Pin a sequential PRE fb POST program is the only effective alternative to control ALS-inhibitor–resistant Palmer amaranth in Nebraska. The use of dimethenamid-Pin a sequential PRE fb POST program, alone or mixed with foliar-active herbicides should be considered by dry edible bean growers who are dealing with ALS-inhibitor-resistant Palmer amaranth.

In Vitro Safening of Bentazon by Melatonin in Sweetpotato (Ipomoea batatas)

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.

Estrategias químicas de manejo de malezas en la habichuela (Phaseolus vulgaris L.) con riego por goteo.

Dos experimentos simultáneos se realizaron en Juana Díaz e Isabela, Puerto Rico, para evaluar cinco estrategias químicas y el cultivo mecánico en el control de malezas en habichuela (Phaseolus vulgaris L.) cv. Arroyo Loro establecida bajo riego por goteo. Las estrategias fueron 1) trifluralin (0.75 kg/ha) presiembra incorporado (PSI), seguido de (sd) bentazon (0.75 kg/ha) y sethoxydim (0.37 kg/ha) postemergente (POST); 2) bentazon (0.75 kg/ha) POST sd sethoxydim (0.37 kg/ha) POST; 3) metolachlor (2.80 kg/ha) preemergente (PRE) sd bentazon (0.75 kg/ha) y sethoxydim (0.37 kg/ha) POST; 4) imazethapyr (0.06 kg/ha) PRE sd bentazon (0.75 kg/ha) y sethoxydim (0.37 kg/ha) POST; 5) trifluralin (0.75 kg/ha) PSI; y 6) cultivo mecánico. El cultivo mecánico se efectuó en todas las parcelas cuatro semanas después de la siembra (SDS). El riego por goteo se aplicó tres veces por semana hasta dos semanas antes de la cosecha de habichuelas secas. El metolachlor PRE sd bentazon POST causó 40% de fitotoxicidad a la habichuela en Juana Díaz, siendo el efecto significativo (P < 0.05) a las 3 SDS, y disminuyendo a 6% a las 6 SDS. Bentazon POST, imazethapyr PRE sd bentazon POST y metolachlor PRE sd bentazon POST causaron 20% de fitotoxicidad a las 3 SDS en Isabela, disminuyendo a menos de 8% a las 6 SDS. En Juana Díaz, trifluralin PSI solo o sd bentazon POST y metolachlor PRE sd bentazon POST redujeron la densidad de malezas de hoja ancha a las 3 SDS en 71, 95 y 55%, respectivamente, comparado con las parcelas no tratadas. A las 6 SDS, trifluralin PSI sd bentazon y sethoxydim POST y metolachlor PRE sd bentazon y sethoxydim POST redujeron la densidad de gramíneas en 85% y 94%, respectivamente. Trifluralin PSI, imazethapyr PRE y metolachlor PRE, todos en combinación con bentazon y sethoxydim POST, al igual que trifluralin PSI solo, a las 3 SDS en Isabela, redujeron la densidad de malezas de hoja ancha en 80%, 53%, 61% y 76%, respectivamente. La estrategia de trifluralin PSI sd bentazon y sethoxydim POST aumentó (68%) el rendimiento de habichuelas verdes en Isabela comparado con el del cultivo mecánico. Trifluralin PSI sd bentazon y sethoxydim POST también mejoró el rendimiento de habichuelas secas en Juana Díaz, con 55% de aumento. Todas las estrategias químicas, excepto bentazon sd sethoxydim POST, aumentaron el rendimiento de habichuelas secas en Isabela, comparados con el cultivo mecánico. Los resultados obtenidos confirman la efectividad de las estrategias químicas basadas en trifluralin PSI, metolachlor o imazethapyr PRE, cualquiera de éstos solo o seguido por bentazon y sethoxydim POST, en el combate de malezas en la habichuela con riego por goteo.

Weed Management in Imidazolinone-Resistant Corn with Imazapic

Field studies were conducted in 1992 and 1993 to evaluate imazapic alone and in postemergence (POST) mixtures with atrazine or bentazon for weed control in imidazolinone-resistant corn treated with carbofuran. Nicosulfuron and nicosulfuron plus atrazine also were evaluated. Imazapic at 36 and 72 g ai/ha controlled large crabgrass 85 and 92%, respectively, which was equivalent to control obtained with nicosulfuron plus atrazine. Imazapic at the higher rate controlled large crabgrass better than nicosulfuron alone. Imazapic at 36 and 72 g/ha controlled Texas panicum 88 and 99%, respectively, and at the higher rate control was equivalent to that obtained with nicosulfuron alone or in mixture with atrazine. Imazapic plus bentazon POST controlled Texas panicum less than imazapic at the lower rate applied alone. Redroot pigweed was controlled 100% with all herbicide treatments. Imazapic at either rate alone or in tank mixture with bentazon or atrazine controlled prickly sida >99%, which was superior to control obtained with nicosulfuron or nicosulfuron plus atrazine. Smallflower, entireleaf, ivyleaf, pitted, and tall morningglories were controlled 96% or greater with all herbicide treatments except nicosulfuron alone. Sicklepod control was >88% with all imazapic treatments, whereas control from nicosulfuron alone was 72%. Corn yields were improved by the addition of POST herbicides with no differences among POST herbicide treatments.

Broadleaf weed control in chickpeas (Cicer arietinum), faba beans (Vicia faba) and lentils (Lens culinaris)

Field experiments were conducted to evaluate the efficacy of herbicides applied alone or in combination for broadleaf weed control in chickpeas, faba beans and lentils. Herbicide applications of metribuzin pre-emergence; pendimethalin pre-emergence; bentazon post-emergence; metribuzin pre-emergence followed by bentazon post-emergence; and pendimethalin pre-emergence followed by bentazon post-emergence were examined and compared to weedy and hand-weeded plots. In chickpeas, metribuzin provided substantial control of broadleaf weeds; however, some injury was observed. Pre-emergence applications in faba beans provided substantial control of broadleaf weeds, and the bean yield was comparable to hand-weeded plots. No additional advantage was observed from combining bentazon with pre-emergence applications. Lentil plants were sensitive to herbicide applications, which caused crop injury and reduced the seed yield significantly.

Diclosulam Systems for Weed Management in Peanut (Arachis hypogaea L.)1

Abstract: Field studies were conducted at Lewiston and Rocky Mount, NC, in 1996 and 1997 to evaluate weed control and peanut response to preplant incorporated (PPI) treatments of diclosulam alone and in systems with postemergence (POST) commercial standard herbicides. All plots received ethalfluralin PPI at 840 g ai/ha. In both years, ethalfluralin plus diclosulam PPI at 17 or 26 g ai/ha followed by (fb) acifluorfen plus bentazon POST, paraquat plus bentazon POST, or imazapic POST controlled common lambsquarters, ivyleaf morningglory, pitted morningglory, prickly sida, smooth pigweed, spurred anoda, and yellow nutsedge in a manner similar to or better than did the commercial standards of ethalfluralin PPI fb metolachlor preemergence (PRE) fb acifluorfen plus bentazon or ethalfluralin PPI fb acifluorfen plus bentazon POST. Yield from peanut treated with diclosulam systems that included POST herbicides was equivalent to or higher than that from peanut treated with ethalfluralin PPI fb metolachlor PRE fb aci...

Weed Management with Diclosulam in Peanut (Arachis hypogaea)1

Field experiments were conducted at three locations in North Carolina in 1998 and 1999 and one location in Virginia in 1998 to evaluate weed management systems in peanut. Treatments consisted of diclosulam alone preemergence (PRE), or diclosulam plus metolachlor PRE alone or followed by (fb) bentazon plus acifluorfen postemergence (POST). These systems were also compared with commercial standards of metolachlor PRE fb bentazon plus acifluorfen POST or imazapic POST. Our data indicate that diclosulam PRE plus metolachlor PRE in conventional tillage peanut production usually controlled common lambsquarters, common ragweed, prickly sida, and entireleaf morningglory. But control of spurred anoda, goosegrass, ivyleaf morningglory, large crabgrass, and pitted morningglory by this system was inconsistent and may require additional POST herbicide treatments. Systems that included diclosulam plus metolachlor PRE consistently provided high yields and net returns.Nomenclature: Acifluorfen, bentazon, diclosulam, imazapic, metolachlor; common lambsquarters, Chenopodium album L. #3 CHEAL; common ragweed, Ambrosia artemisiifolia L. # AMBEL; entireleaf morningglory, Ipomoea hederacea var. integruiscula Grey # IPOHG; goosegrass, Eleusine indica (L.) Gaertn. # ELEIN; ivyleaf morningglory, Ipomoea hederacea (L.) Jacq # IPOHE; large crabgrass, Digitaria sanguinalis L. Scop. # DIGSA; pitted morningglory, Ipomoea lacunosa L. # IPOLA; prickly sida, Sida spinosa L. # SIDSP; spurred anoda, Anoda cristata L. # ANVCR; peanut, Arachis hypogaea L. ‘NC 10C’, ‘NC 12C’.Additional index words: Economic analysis.Abbreviations: fb, followed by; POST, postemergence; PPI, preplant incorporated; PRE, preemergence.

Economic evaluation of HADSS™ computer program in North Carolina peanut

Abstract Field studies were conducted at four locations in North Carolina in 1998 and 1999 to evaluate a computer program, Herbicide Application Decision Support System (HADSS™), for weed management in peanut (Arachis hypogaea). Weed management systems included metolachlor or ethalfluralin preplant-incorporated (PPI) used alone or in combination with diclosulam preemergence (PRE) or flumioxazin PRE. These herbicide combinations were used alone, followed by (fb) postemergence (POST) herbicides recommended by HADSS™ or fb a standard POST program of paraquat plus bentazon early postemergence (EPOST) fb acifluorfen plus bentazon POST. The standard POST herbicide system and HADSS™ POST recommendations were also used without soil-applied herbicides. Ethalfluralin PPI alone controlled large crabgrass (Digitaria sanguinalis) better than metolachlor PPI. Combinations of metolachlor or ethalfluralin PPI with either diclosulam or flumioxazin PRE provided equivalent control of all weeds evaluated except yellow nutsed...

Management of Acetolactate Synthase (ALS)-Resistant Common Sunflower (Helianthus annuusL.) in Soybean (Glycine max)1

Field studies were conducted in 1998 and 1999 to evaluate the sensitivity of a common sunflower population to acetolactate synthase (ALS)-inhibiting herbicides and evaluate alternative control methods for ALS-resistant common sunflower in soybean. Imazaquin, imazethapyr, imazamox, flumetsulam, chlorimuron, cloransulam, and CGA277476 provided 35 to 73% control of common sunflower with labeled rates. Postemergence glyphosate and sequential applications of bentazon effectively controlled ALS-resistant common sunflower. Although pendimethalin imazaquin imazethapyr preemergence followed by glyphosate postemergence with and without cultivation provided 100% control of ALS-resistant common sunflower, sequential applications of glyphosate provided net incomes approximately $50 to $110/ha higher than the alternative control methods. Pendimethalin preemergence followed by acifluorfen bentazon postemergence followed by bentazon 10 d later provided the lowest overall weed control and net income. In treatments with a soil-applied herbicide followed by glyphosate postemergence, cultivation generally did not improve weed control. Soybean yields were the same comparing glyphosate with a soil-applied herbicide followed by glyphosate.Nomenclature: Acifluorfen, bentazon, chlorimuron ethyl, cloransulam, flumetsulam, glyphosate, imazamox, imazaquin, imazethapyr, CGA277476, pendimethalin, common sunflower, Helianthus annuus L. #3 HELAN; soybean, Glycine max (L.) Merr. ‘Asgrow 3601 RR*STS’.Additional index words: Cultivation, herbicide resistance, sulfentrazone, Amaranthus rudis Sauer, Ipomoea hederaceae (L.) Jacq., Setaria faberi Herrm., Xanthium strumarium L., AMATA, IPOHE, SETFA, XANST.Abbreviations: ALS, acetolactate synthase; cec, cation exchange capacity; CV, coefficient of variation; MPOST, mid postemergence; OM, organic matter; PRE, preemergence; WAT, weeks after treatment.

Economic Evaluation of Diclosulam and Flumioxazin Systems in Peanut (Arachis hypogaea1

Abstract: Field studies were conducted at two locations in North Carolina in 1998 and in 1999 to evaluate weed control and peanut response following diclosulam at 27 g ai/ha preemergence (PRE) or flumioxazin at 87 g ai/ha preemergence (PRE) alone and in systems with postemergence (POST) commercial standards. All plots received a preplant incorporated (PPI) treatment of metolachlor at 1,400 g ai/ha. Metolachlor PPI plus diclosulam or flumioxazin PRE controlled common lambsquarters, common ragweed, entireleaf morningglory, large crabgrass, and yellow nutsedge as well as or better than metolachlor PPI followed by (fb) acifluorfen plus bentazon POST or paraquat plus bentazon early postemergence fb acifluorfen plus bentazon POST. Metolachlor PPI plus diclosulam PRE or flumioxazin PRE controlled ivyleaf morningglory as well as metolachlor PPI fb acifluorfen plus bentazon POST. Metolachlor PPI plus flumioxazin PRE controlled common lambsquarters better than metolachlor PPI plus diclosulam PRE while diclosulam PR...

Integration of Cropping Practices and Herbicides Improves Weed Management in Dry Bean (Phaseolus vulgaris)1

A field study was conducted to determine the combined effects of row spacing, plant density, and herbicides on weed management and dry bean (Phaseolus vulgaris) yield. In weed-free dry bean, a reduction in row spacing from 69 to 23 cm increased yield by 19% and an increase in density from 20 to 50 plants/m2 increased yield by 17%. In the presence of weeds, narrow rows and high plant densities increased dry bean yield, but without herbicides, yields remained low. However, when combined with herbicides, narrow-row and high-density production practices resulted in better weed control and higher dry bean yield than that attained in a wide-row and low-density production system. Herbicide combinations, often at reduced rates, controlled weeds as well or better than the full rate of any individual herbicide. Ethalfluralin applied preplant incorporated followed by reduced rates of imazethapyr or bentazon postemergence (POST) consistently controlled weeds. Imazamox exhibited the potential to provide a total POST weed control option in dry bean production. Information gained in this study will be used to develop improved weed management programs appropriate for either wide- or narrow-row dry bean production systems.Nomenclature: Bentazon, 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2- dioxide; ethalfluralin, N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl)benzenamine; imazamox, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-(methoxymethyl)-3-pyridinecarboxylic acid; imazethapyr, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-ethyl-3-pyridinecarboxylic acid; small red dry bean, Phaseolus vulgaris L. ‘Ember.’Additional index words: Integrated weed management, plant density, row spacing, ECHCG, POLCO, POLSC, SETVI, SOLSA.Abbreviations: PAR, photosynthetically active radiation; POST, postemergence; PPI, preplant incorporated.

Response of Peanut (Arachis hypogaea) and Selected Weeds to Diclosulam

Field studies were conducted at five locations in North Carolina and Virginia during 1996 and 1997 to evaluate weed control, peanut (Arachis hypogaea) response, and peanut yield following diclosulam applied preplant incorporated (PPI) and in systems with commercial herbicide standards. All plots received a PPI treatment of ethalfluralin at 840 g ai/ha. Ethalfluralin plus diclosulam controlled entireleaf morningglory (Ipomoea hederaceavar.integriuscula), ivyleaf morningglory (I. hederacea), pitted morningglory (I. lacunosa), common lambsquarters (Chenopodium album), eclipta (Eclipta prostrata), and prickly sida (Sida spinosa) as well as and frequently better than ethalfluralin PPI followed by (fb) acifluorfen plus bentazon postemergence (POST), paraquat plus bentazon early postemergence (EPOST) fb imazapic POST, or imazapic POST. Systems with ethalfluralin plus diclosulam PPI at 26 g ai/ha fb acifluorfen plus bentazon POST controlled a broader spectrum of weeds and yielded greater than systems of ethalfluralin PPI fb imazapic POST or ethalfluralin PPI fb acifluorfen plus bentazon POST. Peanut exhibited excellent tolerance to diclosulam PPI at 17, 26, or 35 g/ha.

Weed Management in Peanut (Arachis hypogaea) with Diclosulam Preemergence

Field studies were conducted at five locations in North Carolina and Virginia in 1996 and 1997 to evaluate weed control and peanut (Arachis hypogaea) response to diclosulam that was applied preemergence (PRE) and in systems with commercial standards. All plots received a preplant incorporated (PPI) treatment of ethalfluralin at 840 g ai/ha. Diclosulam controlled common lambsquarters (Chenopodium albumL.), eclipta (Eclipta prostrataL.), entireleaf morningglory (Ipomoea hederaceavar.integriusculaGray), ivyleaf morningglory [Ipomoea hederacea(L.) Jacq.], pitted morningglory (Ipomoea lacunosaL.), and prickly sida (Sida spinosaL.) as well as and frequently better than the commercial standards of acifluorfen plus bentazon applied postemergence (POST), paraquat plus bentazon early POST followed by (fb) imazapic POST, or imazapic POST. Systems with ethalfluralin PPI plus diclosulam PRE at 26 g ai/ha fb acifluorfen plus bentazon POST controlled a broader spectrum of weeds and yielded greater than systems of ethalfluralin PPI fb imazapic POST or ethalfluralin PPI fb acifluorfen plus bentazon POST. Peanut exhibited excellent tolerance to diclosulam PRE at 17, 26, or 35 g/ha.

Weed Control in Navy Bean in Reduced Tillage Systems

Concern over soil erosion and high production costs in conventional tillage systems has led to interest in reduced tillage systems for navy bean (Phaseolus vulgaris L.). Research was conducted for 2 yr at two sites with different soil textures to develop weed management strategies in reduced tillage systems for navy bean. Twelve weed management strategies were evaluated in conventional tillage, no-till, and zone-till systems in 1995 and 1996 in Michigan. Weed management strategies included hand-weeding, cultivation-only, preemergence herbicides, preemergence followed by postemergence herbicides, and postemergence herbicide treatments. Glyphosate was applied to control existing vegetation in the no-till and zone-till systems. Redroot pigweed (Amaranthus retroflexus L.) and common lambsquarters (Chenopodium album L.) populations were lower in the no-till and zone-till systems than in the moldboard plow and chisel plow systems. Imazethapyr plus pendimethalin preemergence provided less weed control than preemergence followed by postemergence and total postemergence treatments in two of four site years. Preemergence followed by postemergence herbicides controlled annual broadleaf weeds better than postemergence herbicides alone. Navy bean seed yield at the sandy clay loam site was 50% higher in moldboard plow and chisel plow tillage systems than in the no-tillage system. The highest average gross margin was in the chisel plow system. There was no difference in navy bean seed yield due to tillage system at the sandy loam site and the no-tillage and zone-tillage systems had the highest gross margins. These data suggest that weeds can be controlled in reduced tillage systems and the success of reduced tillage systems in dry bean production varies by soil texture.

Imazethapyr Systems for Peanut (Arachis hypogaea L.)

Abstract Field studies conducted in 1992 at Tifton and Midville, GA and in 1993 at Attapulgus, GA evaluated imazethapyr systems for weed control, peanut (Arachis hypogaea L.) injury, and yield. The standard of imazethapyr + paraquat early postemergence (EPOST) followed by paraquat + 2,4-DB + bentazon postemergence (POST) controlled at least 87% of bristly starbur, prickly sida, smallflower morningglory, and yellow nutsedge and the peanut crop yielded 3310 kg/ha. This standard controlled Florida beggarweed (46 and 83% control) and sicklepod (74 and 88% control) in 1992 and 1993; respectively. Imazethapyr PPI at 36 and 72 g/ha controlled bristly starbur 78 and 100%, respectively, and controlled prickly sida and smallflower morningglory at least 90%. Imazethapyr PPI at 36 and 72 g/ha controlled yellow nutsedge 83 and 80%, respectively. Imazethapyr did not control sicklepod or Florida beggarweed. Control of these two species and high peanut yields required a POST application of a paraquat mixture.

Lactofen Systems for Broadleaf Weed Control in Peanuts (Arachis hypogaea)

Weed management systems using a chloroacetamide herbicide applied preplant incorporated (PPI) and at cracking (AC) plus lactofen applied AC and early postemergence (POST) controlled at least 98% of common lambsquarters. Similar systems using a chloroacetamide herbicide applied PPI and early POST plus lactofen applied early POST and postemergence (POST) controlled less than 70% of common lambsquarters. All sequential lactofen systems controlled common ragweed completely and at least 86% of morningglory species. Highest peanut yields and net returns were obtained with weed management systems consisting of sequential applications of lactofen applied AC and early POST, or systems that used acifluorfen plus bentazon POST, or lactofen plus bentazon applied early POST or POST.