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Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Weeds, especially ryegrass (Lolium multiflorum), interfere with and at the same time reduce the productivity and grain quality of wheat. The objective of this study was to evaluate the selectivity and efficacy of pre-emergent herbicides used in combination with post-emergent herbicides on wheat to control ryegrass. Two experiments were conducted in a randomized block design with four replicates, one to check selectivity and the other to assess ryegrass control. The variables evaluated were: herbicide phytotoxicity to wheat, ryegrass control, number of ears per area, hectolitre weight, thousand-grain mass and grain yield. The results indicate that pinoxaden showed low phytotoxicity to the crop and high control of ryegrass. S-metolachlor showed phytotoxicity, increasing with higher doses. The application of S-metolachlor + pinoxaden (480 + 40 g ha-1) resulted in the highest grain yield for the TBio Duque and TBio Sossego wheat cultivars. The use of pinoxaden in isolation shows better performance of the grain yield components of the TBio Duque and TBio Sossego wheat cultivars. [ABSTRACT FROM AUTHOR]

The selectivity of the herbicide 2,4-D depends on the plant species, the formulations produced and/or the developmental stages of the plants to which it is applied. The objective of this study was to assess the best stage of development of wheat cultivars for the application of 2,4-D salt formulations. The experimental design consisted of randomized blocks arranged in a factorial scheme (2 x 2 x 4 + 1) with four replicates. The treatments evaluated were wheat cultivars (OR 1403 and TBio Toruk), 2,4-D formulations (amine and choline salts) and crop development stages (before tillering start, at full tillering, first node and booting), another control without herbicides. 2,4-D choline and amine cause greater phytotoxicity when applied at the phenological stage of the first node of the cultivar OR 1403 and less at TBio Toruk. The highest number and length of ears, number of full grains, thousand grain weight, hectoliter weight, grain productivity and lowest number of sterile grains generally occurred when 2,4-D-choline was applied at the first node of the cultivar OR 1403 and when 2,4-D-amine was applied at the rubberization of TBio Toruk. The highest grain yields occurred when 2,4-D-choline and amine were applied to varieties in wheat booting. [ABSTRACT FROM AUTHOR]

AbstractNew technologies developed to control weeds in crops are flourishing in recent years. Therefore, the objective of this work was to study the competitive ability of soybean cultivars C2531E (Enlist®), M6410 IPRO (RR2®) and BRS 257 (conventional), with distinct biotechnological background, when competing against Euphorbia heterophylla and Urochloa plantaginea. Crops and competitors were studied in distinct plant proportions: 24:0; 18:6; 12:12; 6:18 and 0:24 plants per plot. Fifty days after emergence, plant height, leaf area (AL) and aboveground dry mass (DM), photosynthetic and transpiration rates and stomatal conductance were assessed. Crop responses to competition tended to be species-specific. Soybean M6410 IPRO presents better morphophysiological performance compared to C2531E and BRS 257 when it competed against U. plantaginea. The soybean BRS 257 showed greater LA when competing against U. plantaginea. The competitiveness indices showed that M6410 IPRO responses to competition by accumulating aboveground DM while C2531E responsesby increasing LA. There was difference among cultivars in their strategy to deal with the weed competition, and M6410 IPRO had better competitive ability than the other cultivars when it competed against E. heterophylla. [ABSTRACT FROM AUTHOR]

Volunteer corn plants have infested crops sown in succession, causing yield losses. The objective of this study was to evaluate the competitive ability and economic damage level (EDL) of soybean cultivars infested by volunteer corn plants. The experiment was conducted in a randomized block design with one replication. The treatments consisted of six soya cultivars and 12 densities of volunteer corn, hybrid Syngenta 488 Vip 3, established for each cultivar, with a minimum of 0 and a maximum of 130 plants m-2. At 30 days after emergence, the plant density, ground cover, leaf area and dry mass of the aerial part of the volunteer corn plants were quantified. In soybeans, grain yield, control cost, bag price and control efficiency were determined. Dry mass was the variable that best fitted the rectangular hyperbola model. The soybean cultivars Nidera 5909 RG, Syngenta 13561 IPRO and Brasmax Lança IPRO showed greater competitive ability and EDL values of 0.07 to 0.20 plants m-2 in the presence of volunteer corn. The lowest EDL values ranged from 0.02 to 0.12 plants m-2 for the cultivars Dom Mario 5958 RSF IPRO, Nidera 6909 IPRO and Brasmax Lança IPRO, which were the least competitive. [ABSTRACT FROM AUTHOR]

Among the factors that affect potato productivity, the interference caused by weeds stands out as they may compete with the crop, release allelopathic substances to soil and host insects and diseases. Therefore, the objective of this work was to assess the competitive ability of white (Aghata) and pink (Asterix) potato cultivars when infested by Alexandergrass (Urochloa plantaginea) or wild poinsettia (Euphorbia heteroplylla). The experiment was carried out into greenhouse in randomized blocks design, with four replications. A single potato plant faced competition by either Alexandergrass or wild poinsettia, ranging from 0 to 64 plants per plot. Fifty days after seedling transplanting, variables related to the morphophysiology of potato cultivars and weeds were assessed. Potatoes have low competitive ability with both weed species, with wild poinsettia being the most aggressive in reducing the accumulation rates of leaf area and aboveground dry mass. Potato photosynthetic rate is negatively influenced by the presence of both weeds. Internal CO2 concentration, stomatal conductance, carboxylation efficiency and transpiration rates of potato varied depending on weed species and density. Morphological parameters are reduced when potato competed with Alexandergrass or wild poinsettia; however the physiological parameters are most sharply affected when under competition with wild poinsettia. [ABSTRACT FROM AUTHOR]

Copyright of BIOAGRO is the property of Revista BIOAGRO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sustainable weed management strategies are important for reducing chemical inputs and development of weed resistance. This study aimed to evaluate the effect of extracts from winter cover crops (cereal rye, black oat, forage turnip, and common vetch) and summer cover crops (jack bean, velvet bean, and brown hemp) on seed germination and seedling growth of glossy nightshade (Solanum americanum Mill), under controlled conditions. The aqueous extracts were produced from the shoot biomass of cover crops at concentrations of 0%, 25%, 50%, 75%, and 100%. Fifty S. americanum seeds were placed on Germitest paper moistened with 15 mL of each extract concentration. Cereal rye extract at the highest concentration reduced total germination to 43% and caused a 62% reduction in the germination rate index (GRI) of S. americanum. Velvet bean extract reduced germination, GRI, and seedling growth of S. americanum from the lowest concentration applied, while concentrations of 75% and 100% completely suppressed seedling development. Decomposing cereal rye and velvet bean cover crops have potential to suppress germination and growth of S. americanum. Efficient cover crops could reduce herbicide applications, and thus improve herbicide resistance management. [ABSTRACT FROM AUTHOR]

In canola, yield and grain quality losses occur due to the interference caused by ryegrass (Lolium multiflorum) when infesting the crop. Thus, the objective was to evaluate the interference and identify explanatory variables seeking to determine the level of economic damage (NDE) of different densities of ryegrass infesting canola hybrids. The experiment was carried out in a randomized block design, with one replication. The treatments consisted of five canola hybrids (Hyola 433, Hyola 61, Alht B4, Hyola 575 CL and Hyola 76) and 12 ryegrass densities, from 0 to 260 plants m-2, in competition with the crop. At 50 days after plant emergence, the variables as plant densities, leaf area, soil cover and shoot dry matter of ryegrass plants were evaluated. Grain yield, control cost, grain price and control efficiency were determined in canola plants. The soil cover presented the best fit to the rectangular hyperbola model, adequately estimating the grain yield losses due to ryegrass interference. The canola hybrids Hyola 433 and Hyola 575 CL were the most competitive when compared to the others in the presence of the competitor, with higher values of EDL. The canola hybrids Hyola 433 and Hyola 575 CL showed the highest EDL values with 3.85 to 5.13 plants m-2 in all simulations performed, respectively. The lowest EDL values were obtained with hybrids Hyola 61, Alht B4 and Hyola 76 with average variations of 1.02 to 2.15 plants m-2, respectively. The canola grain yield, grain bag price, efficiency of the herbicide, and the reduction in the control cost cause variation in the economic damage level values. [ABSTRACT FROM AUTHOR]

A pesquisa teve por objetivo avaliar os componentes de produção e a produtividade do cultivar de arroz híbrido de sequeiro Ecco comparado as cultivares convencionais BRS Primavera, BRS Sertaneja e Cambará nos municípios de Vilhena e Cerejeiras-RO. O delineamento experimental utilizado foi inteiramente ao acaso com quatro repetições. Os experimentos foram instalados no mês de novembro de 2009, sendo um na Fazenda Experimental da Faculdade da Amazônia, no município de Vilhena-RO, localizada a uma latitude S 12º44'26" e a uma longitude 60º08'45" W, e o outro, também em Campo experimental da Faculdade da Amazônia no município de Cerejeiras-RO localizadoS 13°11'19.6" de latitude e W 060°51'43,9" de longitude.As variáveis avaliadas foram: perfilhamento, número de grãos inteiros e chochos por panícula, peso de 1000 grãos, produtividade em sacas de 60 kg por hectare e rendimento de grãos inteiros.O cultivar híbrido Ecco é o mais indicado para o cultivo nas duas regiões, pois apresentou melhor perfilhamento, maior eficiência no enchimento de grãos, maior peso de 1000 grãos e consequentemente maior produtividade nos dois municípios, além de um alto rendimento de grãos inteiros em relação aos outros cultivares

Copyright of Revista de Ciencias Agricolas is the property of University of Narino, Faculty of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study of interference and the economic damage level (EDL) of weeds in crops allows more rational management measures to be adopted. Given this, it was the aim of this study to determine the competitive ability and EDL of quinoa genotypes in the presence of alexandergrass. Treatments consisted of three quinoa genotypes (Q 1303, Q 1331, and Q 1324), which competed with 12 alexandergrass densities: 0, 16, 36, 40, 44, 52, 60, 84, 280, 532, and 1,036; 0, 8, 28, 32, 48, 52, 60, 72, 84, 820, and 988; and, 0, 8, 36, 44, 48, 60, 68, 80, 84, 120, 756, and 848 plants m-2, respectively. Alexandergrass plants were evaluated for plant density (PD), ground cover (GC), leaf area (LA), and aerial dry mass (ADM). In quinoa, grain yield, control cost, selling price, and control efficiency were determined. The quinoa genotype Q 1331 shows greater competitive ability when compared to Q 1303 and Q 1324. EDL values varied from 1.81 to 11.74 plants m-2 for genotype Q 1331, which was more competitive in the presence of alexandergrass. The lowest EDL values ranged from 1.21 to 8.12 plants m-2, for the genotypes Q 1303 and Q 1324, which have the lowest competitiveness with the competitor. [ABSTRACT FROM AUTHOR]

Solanum americanum is a weed found in many important crops and is characterized by high production of fruits and seeds. Knowledge of the biology of the species is essential for efficient weed control so that the best control strategies and combinations thereof can be developed. Therefore, the aim of this study was to determine the environmental factors that affect germination and emergence of S. americanum. Six experiments were conducted in the laboratory, simulating field situations in which germination was tested under different pH conditions, osmotic and saline stress, the effect of aluminum content, and different covers and straw levels. Germination and seedling emergence were evaluated, depending on the objectives of the experiment. We found that the germination changed according to the increase in salinity and the decrease in osmotic potential of the soil. The same was observed to the soil cover and its levels, as the emergence rate decreased with the increase in the amount of straw. Germination was reduced at alkaline pH (9-10). Aluminum had no effect on germination, only on normal seed development. Highlighted Conclusion 1. Increasing the amount of straw in the soil reduced the germination of S. americanum. 2. At alkaline pH, germination of S. americanum was reduced. 3. Aluminum had a negative influence on the development of S. americanum. [ABSTRACT FROM AUTHOR]

Rootstock contributes to increase the absorption and nutrients translocation efficiency. We aimed to characterize rootstocks according to the nutritional physiological state of the scion cultivar. The experiment was carried out during three periods of leaf collect on the 4-year old peach cv. BRS Libra budded onto 21 rootstocks cultivated in a high density orchard. The following traits were evaluated: xylem water potential, dry leaf mass and chemical leaf nutritional analysis. The collected data were submitted to analysis of variance by the F test and some genetic parameters were estimated. When significant, the means were compared using the Scott-Knott test, at 5% significance. The principal component analysis was performed to verify the interrelationships between the rootstocks and the evaluated traits. The deviation from optimum percentage index was used to select the most nutritional stable rootstock. We observed that rootstock affects the dynamic absorption nutrient parameters in interactions with the scion. The highest foliar levels of P were found in the BRS Libra cultivar when budded onto the rootstocks 'Santa Rosa', 'Barrier', 'Tsukuba-1' and 'Rosaflor'. The leaf analysis revealed a high variation in the mineral nutritional status among the studied Prunus rootstocks. Most of the mineral macro-elements varied between medium and optimal levels. The rootstocks 'Rigitano' and 'Nemared' showed greater supply of nutrients to the canopy of 'BRS Libra'. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Lolium multiflorum Lam. is a winter weed of difficult control found as diploid (2n) and tetraploid plants (4n). Our study aimed to evaluate the responses of antioxidant enzymes and lipid peroxidation, in both diploid and tetraploid ryegrass varieties. Treatments consisted of control plants (without any herbicide application), and four herbicides with different mechanisms of action. Leaf material was collected 36 h after treatment imposition to determine the lipid peroxidation by ferrous oxidation-xylenol (FOX) content, and the activity of the enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), glutathione-S-transferase (GST), and δ-aminolevulinic acid dehydratase (ALAD). Both ryegrass varieties showed oxidative stress mainly due to a downregulated decreased (>31%) in SOD activity and an increase (>32%) in lipid peroxidation (FOX), mainly in ryegrass genotypes exposed to haloxyfop, glyphosate, and iodosulfuron. On the other hand, clethodim-treated plants had an increase in SOD and APX activities, associated with a reduced ALAD activity in both 2n (32%) and 4n (11%) genotypes. In general, the 2n genotype was more affected than the 4n genotype. [ABSTRACT FROM AUTHOR]

The study of bean sowing density and the level of economic damage (EDL) caused by alexandergrass (Urochloa plantaginea) are important tools for adequately adopting the integrated management of this weed and, thus, producing food with higher quality and less pesticide residue. Therefore, the objective of this work was to evaluate the interference and the level of the economic damage of alexandergrass in competition with the common bean, estimated as a function of sowing densities of the crop and the weed. The bean cultivar IPR Uirapuru was used. The treatments consisted of four bean densities (140,000; 180,000; 220,000 and 260,000 plants ha-1, respectively) and alexandergrass that varied from 0 to the maximum of 104 plants m-2. The experiment was installed in a Red Aluminoferric Latosol, at the experimental area of the Federal University of the Southern Border, campus Erechim/RS, on 10/31/2016. We used the rectangular hyperbola model to describe the relationship between the loss of bean grain yield and the explanatory variables of plant density (DP), soil cover (CS), leaf area (AF) and shoot dry matter (MS). Therefore, the variables CS and DP can be used instead of AF and MS to estimate grain yield losses in common beans. The density of 260,000 plants ha-1 of bean showed greater competitiveness with alexandergrass and the highest values of EDLs, justifying the adoption of weed control management at higher densities. [ABSTRACT FROM AUTHOR]

Among the weeds that infest soybeans, the morning glory (Ipomoea indivisa) stands out for competing with water, light, nutrients and also interfering in the crop harvesting process. The aim of this study was to test the competitive ability of soybean cultivars in the presence of I. indivisa, in substitutive experiments. The experiments were carried out in a completely randomized design, with four replicates, using the soybean cultivars M 5838, DM 53i54, DM 57i52, DM 66i68, NS 5445, and NS 6601. A constant final yield for soybean and I. indivisa was observed with 24 plants per pot. Relative and total productivities were analyzed using diagrams applied to substitutive experiments with soybean and I. indivisa plants proportions of 24:0, 18:6, 12:12, 6:18, and 0:24 plants pot-1 (crop:weed). On 35 days after the emergence of the culture and the I. indivisa, the morphophysiological characteristics of the plants were assessed and the relative competitiveness indices were calculated considering the 50:50 plant ratio (12:12 plants pot-1). Morning glory affected the morphophysiological characteristics of soybean cultivars, demonstrating superior competitive ability for environmental resources. There was a competition between soybean cultivars and I. indivisa, which caused reductions in the shoot dry matter for both species. In this study, interspecific competition was more harmful than intraspecific competition. [ABSTRACT FROM AUTHOR]

This study aimed to assess the interference and threshold level (TL) of Sida rhombifolia, the arrowleaf sida, competing with different soybean cultivars. The treatments comprised different soybean cultivars (NS 6909, NA 5909, DM 5958, Brasmax ELITE, Brasmax LANÇA, and SYN 13561) and densities of arrowleaf sida plants per square meter (m-2) (0, 2, 3, 4, 9, 15, 16, 23, 22, and 58; 0, 2, 3, 3, 6, 6, 10, 11, 18, and 47; 0, 3, 4, 7, 8, 10, 11, 13, 15, and 24; 0, 1, 4, 6, 12, 18, 19, 31, 44, and 50; 0, 4, 5, 6, 9, 13, 17, 20, 20, and 47; 0, 2, 3, 5, 9, 11, 15, 18, 29, and 30, respectively) for each cultivar. Cultivars NS 6909, NA 5909, and Brasmax Lança were more competitive than DM 5958, Brasmax Elite, and SYN 13561. The TL values varied from 0.55 to 0.95 plants m-2 for cultivars NS 6909, NA 5909, and Brasmax Lança, which exhibited greater competitiveness with arrowleaf sida. The lowest values of TL varied from 0.26 to 0.61 plants m-2 for cultivars DM 5958, Brasmax Elite, and SYN 13561, which had less competitiveness with weed. [ABSTRACT FROM AUTHOR]

The herbicide 2,4-D is available in distinct formulations in terms of selectivity to non-target species, and in terms of drift and volatilization potentials. Thus, the objective of this work was to evaluate the selectivity and effect of 2,4-D formulations (amine salt and choline) applied at different developmental stages of barley. The experiment was installed in the field in randomized blocks, in a 2 x 4 + 1 factorial scheme, with four replications. Factor A comprised the formulations of 2,4-D (amine salt and choline), and factor B the crop phenological stage (before tillering start, at full tillering, first node and booting), plus a weeded control treatment. The 2,4-D amine showed higher phytotoxicity when applied before tillering and at the first node. On the other hand, 2,4-D choline, when used prior to tillering start, showed the highest phytotoxicities. The yield components showed positive results when using the amine salt before and at tillering, while in the first node stage, and in booting, the choline salt stood out. The use of 2,4-D amine in tillering and choline in the first node provided the highest grain yield of barley. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the competitive ability of carioca bean cultivars BRS FC104, BRS FC402, IAC Imperador, IAC Milênio, IPR Tangará, and SCS Riqueza in the presence of Alexandergrass (Urochloa plantaginea) in different proportions of plants in association. The experiments were carried out in a greenhouse in a completely randomized design with four replications. The treatments were arranged according to the proportions of beans and Alexandergrass plants: 100:0, 75:25, 50:50, 25:75, and 0:100 or 40:00, 30:10, 20:20, 10:30, and 0:40 plants per pot. The competitiveness of the species was analyzed using diagrams applied to replacement experiments and also through relative competitiveness indices. At 30 days after crop emergence, leaf area (LA), height (HP), diameter (DP), and shoot dry mass (SM) of the plant shoots were measured, as well as variables related to the physiology of the species. There was competition among carioca bean cultivars in the presence of Alexandergrass regardless of the proportion of plants, causing decreases in DP, LA and SM. Basically, there is competition for the same environmental resources between beans and Alexandergrass. [ABSTRACT FROM AUTHOR]

Determination of interference periods, competitive ability and economic threshold level (ETL) are important tools for integrated weed management (IWM) in barley. The objective of the work was to determine the periods of interference, the competitive ability and the ETL of weeds in barley (Hordeum vulgare). Two field experiments were carried out, in a randomized block design, with four replications. In this study, the periods of coexistence and control for ryegrass (Lolium multiflorum) and turnip (Raphanus raphanistrum) infesting barley cultivar, cv. ANA 01 were evaluated. The coexistence periods and/or control were: 0, 7, 14, 21, 28, 35, 42 and 120 days after barley emergence (DAE). In experiment 2the treatments for determination of ETLs were composed by barley cultivars (BRS Suábia, ANA 01, BRS Korbel, BRS Manduri, BRS Cauê and BRS Greta), and turnip densities, from zero (0) to maximum densities of 816, 788, 948, 394, 584 and 618 plants · m−2, in competition with each cultivar. Control of turnip and ryegrass should be adopted in barley in the period between 12 to 22 DAE, which is described as a critical control period. The rectangular hyperbola adequately estimates losses in grain yield due to turnip infestation. There is an effect on the competitive ability of the cultivars in relation to turnip, which resulted in ETLs that ranged from 0.27 to 1.99 plants · m−2 . The cultivars BRS Greta, BRS Suábia, ANA 01 and BRS Manduri were the most competitive in the presence of turnip. [ABSTRACT FROM AUTHOR]

Among the weed species infesting soybean, Alexandergrass (Urochloa plantaginea) is highlighted as one of the most competitive. The objective of this work was to determine the periods of interference of Alexandergrass, and is effects, on morphophysiology and yield components of soybean. Treatments were pooled into two groups: the group "convivence" comprised soybean growing among Alexandergrass for increasing periods: 0, 7, 14, 21, 28, 35 and 42 days after emergence (DAE), as well as along all the crop cycle. The "control" group comprised soybean free from competition for the same time lapses. Forty-two DAE, soybean morphophysiology was assessed. There was no effect of the time lpse of Alexandergrass "control" or "convivence" on soybean physiological performance. Plant height, stem diameter, plant dry mass, leaf area and grain yield components of soybean were, however, affected by Alexandergrass. The critical period of interference prevention comprises 26-41 DAE; the period prior to interference is 26 DAE; and the total period of interference prevention is 41 DAE. [ABSTRACT FROM AUTHOR]

Harvesting seeds at physiological maturity is characterized by preserving the quality of the seeds and preventing them from being exposed to deterioration, but the high humidity makes mechanized harvesting unfeasible at this stage. The objective of this work was to verify the feasibility of applying desiccant herbicides in reduced doses, at different times, to the physical and sanitary quality of carioca bean seeds. The experiment was carried out in a randomized complete block design, in a 2x3x4+1 factorial arrangement, with four replications. The carioca bean plants, cultivar BRS Pérola, were desiccated when the seeds had 42 and 30% water content, with ammonium-glufosinate, saflufenacil and diquat, at doses of 0, 50, 75 and 100% in relation to the average dose recommended for seed desiccation. The additional treatment without application of the desiccant was harvested with 18% water content. Analyzes of thousand seed weight, hectoliter weight, electrical conductivity and sanity test were performed. The use of desiccant herbicides and the increase in their doses, at both times of application, reduces the hectoliter weight, increases the electrical conductivity and increases the incidence of Penicillium spp., Aspergillus spp. and Fusarium spp, however, with minimized values when applying desiccants in reduced doses (50 and 75% of the recommended dose). It is feasible to apply ammonium-glufosinate, saflufenacil and diquat with 30 and 42% of water, to anticipate the harvest when using 50% of the recommended average dose. Harvesting seeds with moisture close to 18% is indicated when there is low rainfall and reduced relative humidity between physiological maturity and harvest. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Ciencias Agricolas is the property of University of Narino, Faculty of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this work was to evaluate the selectivity of herbicides applied alone or in tank mix, and also of combinations of different classes of pesticides (fungicides, herbicides and insecticides) on corn. An experiment was installed in the 2017/18 crop to assess herbicide selectivity, and repeated in 2018/19. The second experiment aimed to assess the selectivity of mixtures of different classes of pesticides, and was installed only in 2017/18. The experimental design adopted in the tests was randomized blocks, with four replicates. In each trial, a total of 16 treatments were evaluated, plus a control. At 7, 14 and 21 days after the application of treatments the phytotoxicity to corn was evaluated and the yield components and grain yield were determined. Herbicides caused low levels of injury to the corn plants, with small variations in yield components, and affected crop yield differently. The mixtures of pesticides promoted low phytotoxicity, affected yield components inconsistently and caused changes in corn yield. Although these herbicides and other pesticides are registered for use in corn crops, application alone or in tank mix of certain molecules can cause losses in grain yield. [ABSTRACT FROM AUTHOR]

Herbicide tank-mixing is often carried out by farmers aiming to control weeds in crops. Thus, it is important to evaluate the effects of these mixtures regarding the selectivity of crops. The aim of this work is to assess the selectivity of increasing doses of herbicides (glyphosate and 2,4-D), applied alone or as a mixture, on maize crop. Two experiments were carried out in randomized blocks, with four replications, during two crop years. The evaluated variables were: phytotoxicity, plant height, stem diameter, ear length, number of rows per ear, number of grains per row, mass of 1,000 grains and grain yield. The herbicide, 2,4-D, when applied in mixture with glyphosate caused severe phytotoxicity symptoms on maize. Grain yield and growth characteristics were not affected by the herbicides applied alone or as a mixture. Increasing doses of 2,4-D caused severe phytotoxicity symptoms on hybrid Status VIP3. Increasing doses of glyphosate did not show phytotoxicity symptoms and are not directly correlated to any injury caused by 2,4-D in the SX 5885 VIP3 maize hybrid. [ABSTRACT FROM AUTHOR]

In the bean crop there are limited options of herbicides to control eudicotyledons weeds in pre-emergence and sulfentrazone presents potential to be used in a weed management program. The aim of this study was to determine the tolerance of a large number of Brazilian bean genotypes to sulfentrazone and their relation with morphophysiological characteristics, associating it to market classes, seed size and their center of origin. It was evaluated the effect of sulfentrazone application (400 g a.i. ha−1) in pre-emergence of 40 Brazilian bean genotypes, 36 of which were common-bean (Phaseolus vulgaris), two cowpeas (Vigna unguiculata), one adzuki bean (Vigna angularis) and one mung bean (Vigna radiata). There was high tolerance variation of the genotypes to sulfentrazone. Morphological parameters were strongly related with relative tolerance. Common bean genotypes that had medium to large seed size (cranberry and carioca) were more tolerant, while small-sized seed genotypes were more sensitive (black). Andean genotypes were more tolerant than Mesoamerican genotypes. Within the Mesoamerican group, medium-sized seed genotypes (carioca beans) were more tolerant than small-sized seed (black beans). Considering only the Vigna genera, cowpea was highly tolerant to sulfentrazone, while mung bean showed intermediary response and adzuki bean was completely sensible. [ABSTRACT FROM AUTHOR]

When not controlled efficiently, weeds in wheat crop stands may affect both the grain quality and yield production. This work aimed to assess the selectivity and efficacy of herbicides applied to control weeds in the wheat cultivar TBIO Sinuelo. Two experiments were set up to assess the selectivity and the efficacy of herbicides applied to wheat in randomized blocks design with four replications. Treatments tested were: iodosulfuron, pyroxsulam, metsulfuron-methyl, 2,4-D, clodinafop-propargyl, [bentazon + imazamox], saflufenacil, bentazon, carfentrazone-ethyl, imazamox, pendimethalin, [sulfentrazone + diuron], plus two control treatments, one weeded and the other infested. The greatest damages to wheat were caused by imazamox and the commercial mixture [bentazon + imazamox] with phytotoxicity of approximately 50%. On the other hand, applying the commercial mixture [sulfentrazone + diuron] allowed the highest wheat grain yield. The use of clodinafop-propargyl and pyroxsulam promoted the best control of Lolium multiflorum, with 100 and 98.25% at 21 days after treatment application, respectively. The control above 90% of Raphanus raphanistrum was reported with iodosulfuron, pyroxsulam, metsulfuron-methyl, 2,4-D, [bentazon + imazamox], saflufenacil, bentazon, and carfentrazone. Clodinafop-propargyl was the most efficient on ryegrass, and iodosulfuron, pyroxsulam, metsulfuron-methyl, 2,4-D, saflufenacil, and carfentrazone performed best on the turnip. Pyroxsulam was the treatment that showed, in both experiments, the best results for all-grain yield components, especially for grain yield. [ABSTRACT FROM AUTHOR]