Fb Bentazon Research Articles

Two-Pass Weed Management Programs for Identity-Preserved Soybean

Weed management is a challenge in Identity-Preserved (IP) soybean in Ontario, Canada. Six experiments were established in southwestern Ontario, Canada during 2021 and 2022 to evaluate weed control and soybean yield with preemergence (PRE), early postemergence (EPOST), and PRE followed by (fb) late POST (LPOST) herbicide programs. At 8 weeks after LPOST herbicide applications, S-metolachlor/metribuzin, pyroxasulfone/sulfentrazone, and flumioxazin/metribuzin/imazethapyr applied PRE provided 7, 49, and 99% control of velvetleaf; 65, 98, and 100% control of green pigweed; 7, 8, and 82% control of common ragweed; 25, 68, and 98% control of common lambsquarters; 91, 77, and 89% control of barnyardgrass; and 62, 68, and 93% control of green foxtail, respectively. Imazethapyr + bentazon applied EPOST provided 91% control of velvetleaf; 91% control of green pigweed; 78% control of common ragweed; 95% control of common lambsquarters; 76% control of barnyardgrass; and 79% control of green foxtail. S-metolachlor/metribuzin, pyroxasulfone/sulfentrazone, and flumioxazin/metribuzin/imazethapyr applied PRE fb bentazon + fomesafen + quizalofop applied LPOST provided 61, 86, and 100% control of velvetleaf; 97, 99, and 100% control of green pigweed; 94, 88, and 99% control of common ragweed; 96, 98, and 100% control of common lambsquarters; 97, 95, and 97% control of barnyardgrass; and 97, 96, and 99% control of green foxtail, respectively. There was minimal and transient soybean injury (6% or less) with all PRE or EPOST herbicide treatments, however, S-metolachlor/metribuzin, pyroxasulfone/sulfentrazone, or flumioxazin/metribuzin/imazethapyr applied PRE fb bentazon + fomesafen + quizalofop LPOST caused up to 22% injury in soybean. Weed interference reduced soybean yield 40%. Weed interference with S-metolachlor/metribuzin and pyroxasulfone/sulfentrazone applied PRE reduced soybean yield 25 and 31%, respectively. Reduced weed interference with flumioxazin/metribuzin/imazethapyr applied PRE, imazethapyr + bentazon applied EPOST, and the two-pass programs of a PRE fb LPOST herbicide resulted in soybean yield that was similar to the weed-free control. This study concludes that there are many effective weed management programs in IP soybean; however, the two-pass weed control programs are recommended since they provide good to excellent weed control, minimize soybean yield loss from weed interference, and ensure the use of multiple herbicide modes of action which reduces the selection intensity for the evolution of herbicide-resistant weeds.

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 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.

Purple Nutsedge (Cyperus rotundus) and Yellow Nutsedge (Cyperus esculentus) Control in Glyphosate-Tolerant Soybean (Glycine max)1

Field studies were conducted to evaluate the effects of glyphosate and conventional herbicides on purple and yellow nutsedges. Tubers collected from the field were counted and tested for viability via growth chamber or triphenyl tetrazolium chloride test to determine the effect of herbicides on tuber density and viability. With purple nutsedge, herbicide treatments containing glyphosate at 0.84 kg/ha followed by (fb) glyphosate at 0.56 kg/ha reduced viable and total tuber density. Among conventional herbicides, treatments containing metolachlor at 2.2 kg/ha plus sulfentrazone at 0.26 kg/ha plus chlorimuron at 0.05 kg/ha applied preemergence (PRE) and metolachlor at 2.2 kg/ha plus imazaquin at 0.14 kg/ha applied PRE fb bentazon at 0.84 kg/ha applied postemergence (POST) reduced total and viable tuber density compared to the nontreated. Metolachlor at 2.2 kg/ha plus sulfentrazone at 0.26 kg/ha plus chlorimuron at 0.05 kg/ha applied PRE fb bentazon applied POST also reduced viable tuber density of purple nutsedge. With yellow nutsedge, all herbicide treatments reduced total and viable tuber density over the nontreated check.Nomenclature: Tetrazolium red; 2,3,5-triphenyl tetrazolium chloride; purple nutsedge, Cyperus rotundus L. #3 CYPRO; soybean, Glycine max (L.) Merr. ‘Asgrow 4701RR’, ‘Hartz 4998’; yellow nutsedge, Cyperus esculentus L. # CYPES.Additional index word: Perennial weeds.Abbreviations: fb, followed by; POST, postemergence; PRE, preemergence; WAP, weeks after planting.

Influence of AC 263,222 Rate and Application Method on Weed Management in Peanut (Arachis hypogaea)

Experiments were conducted in 1991 and 1992 to evaluate the weed control effectiveness from several rates of AC 263,222 applied PPI and PRE (36 and 72 g ai/ha), early POST (EPOST) (18, 36, 54, or 72 g/ha), POST (18, 36, 54, or 72 g/ha), and EPOST followed by (fb) POST (27 fb 27 g/ha or 36 fb 36 g/ha). These treatments were compared to the commercial standard of bentazon at 0.28 kg ai/ha plus paraquat at 0.14 kg ai/ha EPOST fb bentazon at 0.56 kg/ha plus paraquat at 0.14 kg/ha plus 2,4-DB at 0.28 kg ae/ha. Application method had little effect on weed control with AC 263,222. In contrast, application rate affected control. Purple nutsedge, yellow nutsedge, prickly sida, smallflower morningglory, bristly starbur, common cocklebur, and coffee senna were controlled at least 82% with AC 263,222 at 36 g/ha (one-half the maximum registered use rate) regardless of application method. AC 263,222 at 72 g/ha (registered use rate) controlled sicklepod 84 to 93%, Florida beggarweed 65 to 100%, andIpomoeamorningglory species 89 to 99%. A single application of AC 263,222 at 36 g/ha or more controlled all weeds (with the exception of Florida beggarweed) as well or greater than sequential applications of bentazon plus paraquat fb bentazon, paraquat, and 2,4-DB. All rates of AC 263,222 applied POST and all application methods of AC 263,222 at 72 g/ha had better yields than the pendimethalin control.