Postemergence Application Of Bentazon Research Articles

Bio-efficacy of Bentazon against Weeds in Direct Seeded Rice under Kymore Plateau and Satpura Hill Zone

The experiment was conducted at Research Farm of Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur, Madhya Pradesh, India to study the “Bio-efficacy of Bentazon against Weeds in Direct Seeded Rice under Kymore Plateau and Satpura Hill zone” during kharif season of 2016 under edaphic and climatic conditions of Jabalpur (M.P.). The dominant weeds associated with direct seeded rice in the experimental field comprised of monocot like Echinochloa colona and Dinebra retroflexa, sedges like Cyperus iria and dicot weeds including Mullogo pentaphylla and Alternanthera philoxeroides. Experiment consisted of total ten treatments comprising of seven doses of Bentazon 600, 800, 1000, 1200, 1600, 1800 and 2000 g/ha, 2,4-D 380 g/ha as post-emergence, hand weeding twice at 20 and 40 DAS including weedy check, the experiment was laid out in randomized block design (RBD) with 03 replications. The post-emergence application of Bentazon at 1600 g/ha was found economically best suitable for effective control of dicot weeds in direct seeded rice.

Herbicide-Based Weed Management for Soybean Production in the Far Eastern Region of Russia

This study was conducted to establish a weed management system based on the sequential application of pre-emergence (PRE) and post-emergence (POST) herbicides for soybean production in Primorsky krai. Field experiments were conducted for two years in a field located in Bogatyrka, Primorsky krai, Russia (N43°49′, E131°36′). No herbicide application resulted in significant soybean yield loss, 0.03–0.3 t ha−1, which is more than 91.6% yield loss compared with that of the weed-free plot. The PRE application of acetochlor showed good weed control efficacy (greater than 90% weed control) with acceptable soybean safety (less than 10% soybean damage), while the other PRE herbicides performed poorly in terms of weed control. The POST application of bentazon + acifluorfen, bentazon, and imazamox at 30 days after soybean sowing (DAS) showed good weed control efficacy with good soybean safety. Neither the PRE nor POST application alone showed a sufficient soybean yield protection, resulting in much lower soybean yield than the weed-free plot. The sequential application of acetochlor (PRE), followed by either bentazon + acifluorfen (POST) at 30 DAS in 2012 or bentazon + imazamox (POST) at 60 DAS in 2013 showed the best performance in soybean yields, 1.7 t and 1.9 t ha−1, respectively, provided with 724.5 US$ and 1155.6 US$ ha−1 of economic returns. For alternative PRE herbicides of acetochlor, which is now banned, our tests of the sequential application of S-metolachlor with other POST herbicides and the sole application of other PRE herbicides revealed that S-metolachlor and clomazone could also be considered. Our results thus demonstrate that the sequential applications of PRE and POST herbicides should be incorporated into the weed management system for soybean production in Primorsky krai, Russia.

RESPONSE OF SOYBEAN AND ASSOCIATED WEEDS TO VARIOUS WEED CONTROL TREATMENTS

Two field experiments were conducted during two successive seasons of 2007 and 2008 in Meit Nagy Village, Meit Ghamr, Dakahlia Governorate, Egypt, to study the effect of some pre-or post-emergence herbicides either alone or accompanied with hoeing on soybean yield and its components and associated weeds. The results showed that the best treatments in controlling the annual bread leaves, annual grasses and total annual weeds throughout the vegetative period of soybean plants were : The pre-emergence application of Pendimethalin at 0.425 kg a.i./fed or Metribuzin at 0.140 kg a.i./fed followed by one hoeing (21 days after sowing) or post-emergence application of Bentazon at 0.180 kg a.i./fed preceded by one hoeing (21 days after sowing), or using hand hoeing twice (21 and 35 days after sowing) compared with single herbicidal treatments. Treatment of Pendimethalin at 0.425 kg a.i./fed followed by one hoeing improved the growth of soybean plants and resulting in the tallest plants, highest number of pods/plant, number of seeds/pod, seed index, seed yield/plant and per feddan and the highest oil % in the seeds as well as seed protein percentage compared to other weed control treatments.

Corn Response to Mesotrione as Affected by Soil Insecticide, Application Method, and Rate

Corn Response to Mesotrione as Affected by Soil Insecticide, Application Method, and Rate

Tolerance of ‘Salam’ Seashore Paspalum (Paspalum vaginatum) to Postemergence Herbicides

Field studies were conducted to assess the tolerance of seashore paspalum (‘Salam’) to postemergence (POST) herbicides in Florida in 2000 and 2001. POST applications of bentazon (2,200 g/ha), clopyralid (420 g/ha), dicamba (280 g/ha), halosulfuron (70 g/ha), imazaquin (420 g/ha), mecoprop + 2,4-D + dicamba (160 + 180 + 40 g/ha), metsulfuron (30 g/ha), and quinclorac (1,700 g/ha) resulted in ≤10% injury 7 and 15 d after treatment (DAT), indicating their safety for POST application. Clethodim (280 g/ha) and sethoxydim (310 g/ha) caused 67 and 46% injury, respectively, 15 DAT averaged across 2000 and 2001. Ethofumesate was inconsistent between years, causing 30 and 60% injury 7 and 15 DAT, respectively, in 2000, but only 5 and 13% 7 and 15 DAT, respectively, in 2001. Imazapic and trifloxysulfuron-sodium caused an average of 47% injury 7 DAT in 2000 and 45% injury 15 DAT in 2001. Clethodim, ethofumesate, imazapic, sethoxydim, and trifloxysulfuron-sodium can not be safely applied POST to Salam seashore paspalum; however, bentazon, clopyralid, dicamba, halosulfuron, imazaquin, mecoprop + 2,4-D + dicamba, metsulfuron, and quinclorac are safe.

Responses of otebo bean (Phaseolus vulgaris L.) to postemergence herbicides

Ontario otebo bean growers have few herbicide options available for weed management. Six field trials were conducted in Ontario, Canada, over a 2 year period (2003 and 2004) to evaluate the tolerance of otebo bean to the postemergence (POST) application of bentazon at 1080 and 2160 g ai ha−1, fomesafen at 240 and 480 g ai ha−1, sethoxydim at 500 and 1000 g ai ha−1, quizalofop‐p‐ethyl at 72 and 144 g ai ha−1, imazamox plus fomesafen at 25 + 200 and 50 + 400 g ai ha−1, and imazamox plus bentazon at 25 + 600 and 50 + 1200 g ai ha−1. All treatments, including the untreated control, were maintained weed‐free during the growing season. The POST application of bentazon, imazamox plus fomesafen, and imazamox plus bentazon caused as much as 9% visual injury and reduced the plant height ≤ 12%, reduced the shoot dry weight ≤ 32%, and delayed maturity but had no adverse effect on the yield of otebo bean. Fomesafen, sethoxydim, and quizalofop‐p‐ethyl applied POST caused as much as 8% visual injury but this was transient and had no adverse effect on the plant height, shoot dry weight, seed moisture content, and yield of otebo bean, except for quizalofop‐p‐ethyl, which reduced the shoot dry weight as much as 18%. Based on these results, bentazon, fomesafen, sethoxydim, quizalofop‐p‐ethyl, imazamox plus fomesafen, and imazamox plus bentazon applied POST have an adequate margin of crop safety for weed management in otebo bean production in Ontario. However, care must be taken to avoid spray overlaps to prevent injury from bentazon, imazamox plus fomesafen, and imazamox plus bentazon.

Sweet Corn Cultivar Sensitivity to Bentazon

Five sweet corn cultivars were evaluated for tolerance to bentazon in five field experiments conducted during 2 yr in Ontario. Bentazon was applied postemergence (POST) at 1.08 and 2.16 kg ai/ha, the highest registered rate and twice the highest registered rate, respectively, used in sweet corn in Ontario. When bentazon was applied POST at 1.08 and 2.16 kg/ha to sweet corn cultivar ‘DelMonte 2038’, injury included plant stunting and leaf damage ranging from 6 to 69% and 15 to 90%, respectively. Plant height was reduced to 48 and 100% of the untreated check when treated with bentazon at 1.08 and 2.16 kg/ha, respectively. The visual injury and height reductions were reflected in the marketable yields, which were reduced to 94% when treated with bentazon. Significant reductions in height and marketable yield were not observed in the other four cultivars tested. No correlation was observed between bentazon sensitivity and endosperm genotype. Based on visual injury ratings, sweet corn height, and marketable yield, it was concluded that ‘Calico Belle’, ‘GH 2684’, ‘Reveille’, and ‘Rival’ are tolerant to POST application of bentazon.

Responses of black and cranberry beans (Phaseolus vulgaris) to post-emergence herbicides

There is a limited number of post-emergence (POST) herbicides available for weed management in black and cranberry beans in Ontario. The tolerance of two cultivars of black beans (AC Harblack and Midnight Black Turtle) and two cultivars of cranberry beans (Hooter and SVM Taylor) to POST applications of bentazon, bentazon plus fomesafen and imazamox plus fomesafen was evaluated at the maximum-use dose (1×) and twice the maximum-use dose for soybeans (2×) at two Ontario locations in 2001 and 2002. There were no differences between AC Harblack and Midnight Black Turtle or Hooter and SVM Taylor cultivars in their responses to the POST herbicides tested. The POST application of bentazon, bentazon plus fomesafen and imazamox plus fomesafen at 7 DAT caused only minor crop effects in dry beans. At 14 DAT visual injury ratings were higher in black beans (1.4–3.0%) compared to cranberry beans (0.4–1.6%). Visual injury was minimal at 28 DAT and was below 1% for all cultivars and market classes. The POST application of bentazon, bentazon plus fomesafen and imazamox plus fomesafen at the single or double-use rate caused no significant effect on plant height, shoot dry weight, seed moisture content and yield of black or cranberry beans compared to the untreated. Black and cranberry beans were more sensitive to bentazon and bentazon plus fomesafen than imazamox plus fomesafen. Based on these results, there is sufficient tolerance for use of these herbicides post-emergence in black bean and cranberry bean production in Ontario.

Efficacy of Bentazon and MSMA as Affected by a Humic Acid-Type Polymeric Polyhydroxy Acid Adjuvant

Foliar applications of14C-bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] with PPA (polymeric polyhydroxy acid) at 1 or 2% (v/v) or nonoxynol (9.5 POE) [α-(p-nonylpheny1)-ω-hydroxypoly(oxyethylene)] at 1% (v/v) or mixtures of PPA and nonoxynol did not increase absorption or translocation of14C-bentazon in soybeans [Glycine max(L.) Merr. ‘Lee 74′] or common cocklebur (Xanthium strumariumL. # XANST). PPA alone at 1 to 2% (v/v) did not significantly affect absorption or translocation of14C-bentazon in smooth pigweed (Amaranthus hybridusL. # AMACH), but PPA with nonoxynol significantly increased translocation out of the treated leaf. Both PPA and nonoxynol decreased absorption and movement of14C-MSMA [monosodium salt of methylarsonic acid] out of the treated leaf of johnsongrass [Sorghum halepense(L.) Pers. # SORHA]. In greenhouse research, PPA at 0.25 and 0.5% (v/v) did not increase the level of control of common cocklebur obtained following postemergence applications of bentazon at 0.24 and 0.48 kg ai/ha. Similarly, PPA at 0.25 and 0.50% (v/v) did not increase the toxicity of MSMA at 0.3 and 0.6 kg ai/ha to either johnsongrass or common cocklebur.

Variation in Growth Habit and Response to Chemicals among Three Common Cocklebur (Xanthium strumarium) Selections

Burs of common cocklebur (Xanthium strumarium L.) obtained from Stoneville, Mississippi; Urbana, Illinois; and Lamberton, Minnesota, were used in greenhouse and growth chamber studies. The Mississippi and the Illinois strains were both classified as being in the “strumarium” complex of X. strumarium, whereas, the Minnesota strain was classified as being in the “hybrid” complex. The Minnesota common cocklebur developed branch leaves in the leaf axils of the main stem to a much greater extent than did the Mississippi and Illinois common cocklebur. The Mississippi common cocklebur was frequently more tolerant of postemergence applications of bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] than were the Illinois and Minnesota common cockebur. The Mississippi and Illinois common cocklebur developed leaf necrosis when sprayed with an insecticide formulation containing malathion (o, o-dimethyl phosphorodithioate of mercaptosuccinate) and petroleum solvents; the Minnesota common cocklebur did not.

Bentazon Applied Postemergence for Economical Control of Common Cocklebur in Soybeans

Effectiveness of bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide] for control of common cocklebur (Xanthium pensylvanicumWallr.) in soybeans [Glycine max(L.) Merr.] was evaluated in field research over a 3-yr period. Bentazon, applied over-the-top at 0.6 to 1.1 kg/ha, controlled common cocklebur more effectively than over-the-top or directed applications of dinoseb (2-sec-butyl-4,6-dinitrophenol) at 0.8 to 1.7 kg/ha or 2,4-DB [4-(2,4-dichlorophenoxy)butyric acid] at 0.2 kg/ha. Single applications of bentazon were highly effective for control of common cocklebur, but multiple applications usually provided the best control and highest soybean yields. A preemergence treatment of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] at 1.1 kg/ha and a postemergence application of bentazon at 1.1 kg/ha provided 92 to 99% control of common cocklebur. Control of common cocklebur with bentazon reduced discounts in harvested soybean seed caused by excessive moisture content and foreign material. The reduction in discounts improved soybean seed grades.

Effects of Simulated Rainfall on Bentazon Activity

Simulated rainfall less than 8 hr after postemergence application of bentazon (3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2, 2-dioxide) reduced its activity on velvetleaf (Abutilon theophrastiMedic.) and common cocklebur (Xanthium pensylvanicumWallr.) in greenhouse studies. In field studies, simulated rainfall less than 24 hr after application reduced bentazon's activity on velvetleaf. on common cocklebur, bentazon's activity was reduced even if simulated rainfall was delayed for more than 24 hr after application. In greenhouse studies, spray adjuvants (vegetable or petroleum oil) were helpful in overcoming the detrimental effects of simulated rainfall. Greenhouse and field studies indicated that soybeans [Glycine max(L.) Merr.] could tolerate bentazon-oil adjuvant combinations.