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Increased broccoli production in the eastern United States necessitates the exploration of novel concepts to improve weed management in this region. Currently, there are minimal selective postemergent herbicide options available for broccoli growers in the southeastern United States. Research was conducted to determine if bentazon, an effective nutsedge herbicide, could be used safely for broccoli when tank-mixed with chelated iron in both greenhouse and field settings. Initial greenhouse screens in Charleston, SC, demonstrated that when 224 g.ha-1 active ingredient of chelated iron was tank-mixed with bentazon, a reduction in injury occurred in most of the cultivars that were evaluated. However, based on injury ratings, yield parameters, and broccoli quality observed in the field, it appears that the applications of chelated iron yielded no positive effects. Furthermore, for some of the broccoli cultivars it appeared to exacerbate bentazon injury in the field. [ABSTRACT FROM AUTHOR]

Core Ideas: Postemergence herbicide applications can cause injury to soybean crops.The use of insecticide seed treatments has been shown to reduce injury from some herbicides following emergence in some crops.No previous research has been conducted to examine any similar instance in soybean.Results from this research indicate insecticide seed treatments are not likely to reduce injury from the postemergence herbicides evaluated in soybean. Weed control in soybean production plays a vital role in producing a high‐yielding crop. An important component of effective weed control programs for many soybean producers is the use of postemergence (POST) herbicide applications; however, some crop injury can accompany these applications. While uncommon, this injury can result in yield loss depending on the severity and timing of application. Previous research has shown that, in rice, some neonicotinoid insecticide seed treatments can act as herbicide safeners in addition to protecting against early‐season insect pests. Neonicotinoid seed treatments are extensively used in soybean production, but their utility as herbicide safeners has not been examined. As such, field trials were conducted in Marianna, AR in 2015 and 2016, in addition to near Colt, AR in 2016, to determine whether a safening effect could be observed using thiamethoxam and clothianidin in soybean following applications of POST herbicides that commonly cause crop injury. Chlorimuron, fomesafen, and 2,4‐DB were applied 21 d after planting. In Marianna in 2016, injury from chlorimuron and fomesafen was reduced 8 and 7% points, respectively, in thiamethoxam‐treated seed. At the same location and evaluation timing, clothianidin‐treated seed reduced injury from 2,4‐DB by 8% points 1 week after application (WAA). Additionally, a seed treatment main effect was observed at Marianna in 2016 both 2 WAA and 4 WAA, where a thiamethoxam seed treatment reduced injury 5 and 6% points, respectively, averaged across all herbicides. Aside from Marianna in 2016, visible injury was not reduced at any location or evaluation timing. Additionally, yield was not impacted by seed treatment at any location. Based on the results from these experiments, the insecticides clothianidin and thiamethoxam, applied as seed treatments, are unlikely to successfully safen the evaluated POST‐applied herbicides that are often injurious to soybean. [ABSTRACT FROM AUTHOR]

This paper presents research conducted during two coffee farming seasons in Costa Rica. The study examined coffee farmers' weed management practices and is presented in the form of a case study of small-scale farmers' use of labor and herbicides in weed management practices. Over 200 structured interviews were conducted with coffee farmers concerning their use of hired labor and family labor, weed management activities, support services, and expectations about the future of their coffee production. ANOVA and regression analyses describe the relationships between farm size, labor, and herbicide use, and three farm types (i.e., conventional, semi-conventional, and organic). Based on findings regarding the amount of labor used to manually control weeds on different types of farms (large farms, small conventional, semi-conventional, and organic farms) I am able to challenge small conventional farmers' perceived need for herbicide use. Semi-structured interviews of coffee farmers and extension workers further revealed a dominant role played by agro-chemical companies in assisting farmers with production problems, and documented a high transaction cost for information provided from elsewhere. Chemical companies hire extension workers to visit farmers at their farms, free of charge, to offer recommendations on how to treat different pest problems, while government and cooperative extension agents charge for the service. There is a need to increase the amount of resources available to the National Coffee Institute to fund one-on-one farmer support services in order to balance the influence of agro-chemical company representatives and allow farmers to make better decisions regarding weed management. [ABSTRACT FROM AUTHOR]

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Abstract: Derivatives of the new class of 3-hydroxy-4-phenyl-5-oxo-pyrazolines were optimized towards both herbicidal activity on key annual grass weed species and selectivity in small grain cereal crops. The generic structure can be separated into three parts for the analysis of the structure–activity relationships, namely the aryl, the dione with its prodrug forms and the hydrazine moiety. Each area appears to play distinct and different roles in overall expression of biological performance which is further beneficially influenced by adjuvant response and safener action. Pinoxaden 6, a novel graminicide for use in wheat and barley incorporating a [1,4,5]oxadiazepane ring, eventually emerged as a development candidate from the discovery and optimization process. [Copyright &y& Elsevier]

Abstract: Aerobic rice systems, wherein the crop is established via direct-seeding in non-puddled, non-flooded fields, are among the most promising approaches for saving water and labour. However, aerobic systems are subject to much higher weed pressure than conventionally puddled transplanted rice (CPTR). Experiments were conducted for 2 years to develop effective and economical methods for managing weeds in aerobic rice grown by direct-seeding or transplanting on flat land or furrow-irrigated raised-bed systems (FIRBS). Total weed dry weight and weed density were lower with CPTR and highest with aerobic direct-seeded rice on a FIRBS (ADSB), followed by aerobic direct-seeded rice (ADSR). In terms of weight grassy weed constituted 78–96% of total weed weight in all systems of rice establishment. Loss of grain yield of rice due to weed competition ranged from 38% to 92%, being the highest in ADSB. Both weed density and dry weight were negatively correlated with rice grain yield. ADSR treatment produced yield and net economic returns similar to CPTR treatment when weeds were controlled. Pretilachlor with safener at 500ga.i.ha−1 applied 3 days after sowing (DAS)/ days after transplanting (DAT) followed by chlorimuron+metsulfuron at 4ga.i.ha−1 applied 21DAS/DAT followed by hand-weeding at 35DAS/DAT could effectively control all the weeds. The next best treatment was cyhalofop-butyl at 120ga.i.ha−1 applied 14DAS/DAT followed by chlorimuron+metsulfuron at 4ga.i.ha−1 applied 21DAS/DAT followed by hand-weeding at 35DAS/DAT. The ADSR was as effective as conventionally puddle-transplanted rice in attaining higher rice grain yield and net returns when weeds were kept under control. [Copyright &y& Elsevier]

The functions of plant glutathione S-transferases (GSTs) under normal growth conditions are poorly understood, but their activity as detoxification enzymes has been harnessed in agriculture for selective weed control. Herbicide safeners protect monocot crops from herbicide injury but have little effect on weedy monocot or dicot species. Protection by safeners is associated with expression of herbicide-metabolizing enzymes including GSTs, but the basis for selective action of safeners between monocots and dicots is not known. To address this question we have studied the response of Arabidopsis (Arabidopsis thaliana) to various safeners. Benoxacor, fenclorim, and fluxofenim did not protect Arabidopsis from herbicide injury but did induce RNA expression of the glutathione-conjugate transporters encoded by AtMRP1, AtMRP2, AtMRP3, and AtMRP4.'These safeners also induced the organ-specific expression of AtGSTU19 and AtGSTF2, two previously characterized Arabidopsis GSTs from different classes of this enzyme family. RNA hybridization, immunoblot, and reporter gene analyses indicated expression of AtGSTU19 induced by safeners predominated in roots. To test the hypothesis that increased expression of AtGSTU19 would be sufficient to provide tolerance to chloroacetamide herbicides, a chimeric gene was produced containing the open reading frame for this GST driven by a constitutive promoter. Plants containing this transgene had a modest increase in AtGSTU19 protein, predominantly in roots, but this had no effect on tolerance to chloroacetamide herbicides. The localized induction of GSTs by safeners in roots of Arabidopsis may explain why these compounds are unable to provide herbicide tolerance to dicot plant species. [ABSTRACT FROM AUTHOR]

MCPA is antagonistic to a range of herbicides but there is limited research on its compatibility with other broad-leaved weed herbicides. In this study we assessed the joint action of MCPA ester and metsulfuron-methyl on Brassica napus L, using the additive dose model (ADM). The fresh weight responses for selected ratios of the mixture were plotted on the ADM and compared to the predicted mixture response at three assessment levels -50, 75 and 90% control. The mixture demonstrated increasing synergism as the response level increased from 50 to 90%. This result for MCPA ester is in marked contrast to that of the MCPA amine formulation, which was shown in previous studies to be antagonistic towards sulfonylurea herbicides. Formulation is the major deciding factor in determining the compatability of phenoxy herbicides with other herbicides. [ABSTRACT FROM AUTHOR]