Solvay (Brazil)

Zinc deficiency usually occurs in maize grown in Brazilian acidic soils. The aim of this study was to evaluate commercial maize cultivars for their Zn uptake and utilization efficiency. A greenhouse experiment using nutrient solution with young plants was carried out at Campinas, State of São Paulo, Brazil, in 2002. Treatments consisted of: 0.0; 0.1; 0.2; 0.4 and 0.8 mg L-1 Zn in the main plots and 24 commercial maize cultivars in the subplots, in a randomized complete block design. Zn concentration in shoot dry matter (SDM) ranged from 28.4 to 41.6 mg kg-1 among cultivars, clearly indicating a dilution effect, since a negative relation between SDM and plant height was shown. Total Zn-shoot content was a good parameter to discriminate cultivars, once correlated with plant height and SDM (r = 0.66** and r = 0.67**, respectively). Analysis of variance and polynomial regression for total Zn-shoot content was highly significant among cultivars and for the interaction cultivar vs Zn-concentration. Plants under low Zn presented up to three-fold differences among efficiency index values (E.I. = 8.59 to 26.42 mg² DM mug-1 Zn). The results with young plants indicated six maize cultivars classified as Zn-efficient and responsive (AG 7575, Tork, AL Bandeirante, AL 34, AGN 2012, Master) and six cultivars classified as efficient non-responsive (P30F33, P30K75, P30F80, AS 1533, DOW 8420 e AL 30). Other nutrient concentrations in the SDM were within normal limits (K, P, Ca, Mg, Cu, Fe, Mn) for maize young plants.

The removal of four pharmaceuticals and personal care products (PPCPs), namely diethyltoluamide (DEET), paracetamol (PAR), caffeine (CAF) and triclosan (TCS) (at a spiked concentration of 25 μg/L), from natural water using the photo (UVC)-Fenton (powdered zero-valent iron, pZVI) process was investigated. The results show that a molar ratio of H2O2/pZVI of 2.0, pZVI concentration of 22.4 mg/L and pH of 3.0 maximised the removal of the target compounds at 71.1%, 100%, 64.2% and 87.1%, for DEET, PAR, CAF and TCS, respectively, after 30 min in Fenton (pZVI) process. When this process was coupled with UVC radiation, 29.6%, 80.3%, 3.1% and 88.4% of DEET, PAR, CAF and TCS, respectively, were removed within the first minute, and 99.0%, 100%, 99.5% and 100%, respectively, were removed after 30 min. The pseudo first-order kinetic model best fitted the degradation data of DEET, PAR and CAF (1–20 min); and because 80% of TCS and PAR degraded within the first minutes, it is suggested to explore the kinetics during the initial period. Characterisations of pZVI after the photo-Fenton (pZVI) process indicated the corrosion of the surface of iron powder and the presence of iron oxides and iron hydroxides. Lower removals of nitrate (35–50%), phosphate (<35%) and total organic carbon (TOC, <18%) were observed, which may be attributed to the small H2O2/pZVI dosage used. Results of this investigation show that the photo-Fenton (pZVI) process has potential for efficient and cost-effective removal of PPCPs.

The present study investigated the degradation of mercaptobenzothiazole (MBT), evaluating homogeneous and heterogeneous systems. An iron mineral residue from the desliming step of iron mining was used as a source in the Fenton-like reaction (advanced oxidation process). A granulometric analysis of the residue was performed and yielded fractions with high hematite (Fe2O3) and low quartz content in sieves from 74 to below 44 mm. In this particle size range, the hematite content from 58.9% to 67.4% and the Brunauer-Emmett-Teller area from 0.1345 to 1.3137 m2 g−1 were obtained. The zeta potential curves as a function of pH were obtained for the residue, the MBT solution and mixtures thereof. The adsorption of MBT in the residue and its degradation through the Fenton-like reaction were investigated. Adsorption tests and the Fenton-like reaction were carried out, where the MBT species and the residue are oppositely charged, yielding, respectively, 10% MBT adsorption on the surface of the residue and 100% MBT degradation by the Fenton-like reaction at pH 3, hydrogen peroxide concentration of 25 mg L−1, residue concentration of 3 g L−1, 200 rpm and 25°C, from a 100 mg L−1 MBT solution. MBT degradation was found to occur mainly by the heterogeneous Fenton-like process.

Special polymers have been used in the manufacture of storage structures and pipelines avoiding corrosive processes during ethanol fuel transport/storage. Therefore, this work investigated comparatively the effects of the ethanol on the physical-mechanical properties of poly (ether ether ketone) (PEEK) and polyamide 11 (PA-11) based on ageing tests. The WAXD and DSC results demonstrated slight reductions on the crystallinity degree of the aged PEEK, contrariwise to what happened with PA-11, where Xcincreased after ageing. However, the results of thermal, thermomechanical and mechanical analysis (TGA, DMTA, tensile and micro-IITs) demonstrated that PEEK is stable and no significant changes were observed in its elastic modulus (Ey≈ 3.4 GPa, E’ andEit≈ 3.7 GPa) or glass transition temperature. PA-11, conversely, was sensitive to ethanol fuel and expressive changes of its physical-mechanical properties were verified. For both materials, a reasonable correlation between crystallinity and mechanical properties was established.

In the way to reduce costs in the poultry production, high densities of birds are adopted in the production systems. Such high densities can lead to an inappropriate environment, compromising the welfare and decreasing the animal performance. In this work we aimed to evaluate the effects of different densities on the productive yield, egg quality and immunological aspects of Japanese quails. It was used 816 Japanese quails, during egg production phase, in a random design, with four treatments (121.43 cm2/bird; 106.25 cm2/bird; 94.44 cm2/bird and 85.00 cm2/bird) with six repetitions each. Results indicate density did not interfere on egg quality and all treatments can be considered excellent, once the Haugh Unit was 88.03. Therefore, higher densities decline the yield, decreasing the eggs weight (10.35 g), the laying percentage (88%), egg mass (9.16 g) and the week average feed consumption (157.35 g). IgY values were higher at smaller cage density, suggesting birds in this condition presented better immunological condition, related to welfare and stress factors, all linked to immunoglobulins IgY.

ABSTRACT: Pinus cultivation without fertilization is a common practice in southern Brazil, which can induce a decline in the availability of phosphorus (P) in the soil. The purpose of this study was to evaluate the changes in phosphorus fractions in a Humic Cambisol subjected to continuous Pinus taeda L. cultivation without fertilization. Two forest stands were evaluated, after 16 years of Pinus cultivation (1st crop) and 49 years (3rd crop), when soil samples were collected (layers 0-10, 10-20, 20-40, 40-60, and 60-80cm) from six trenches per forest. In soil samples, the P contained in organic (Po) and inorganic (Pi) forms was determined by sequential chemical fractionation. Labile inorganic P fractions remained unchanged after the different cultivation periods. However, the labile organic fractions declined from the first to the third cycle (from 70.6 to 39.8mg dm-3 in the 0-10cm layer), indicating that these forms influence the buffering capacity of labile Pi. The moderately labile organic P acted as a P drain, increasing its percentage of the total, from 34.7 to 56.3%, from the first to the third crop. Soil cultivation for 49 years with Pinus taeda resulted in a reduction of the organic P content, indicating that for this soil use, this P form should be used to diagnose P availability and fertilization requirements.

Foram estudados os efeitos de cinco profundidades de semeadura e duas condicoes de luminosidade na germinacao de sementes de baru. As sementes foram plantadas em vasos de plastico de 22,5 cm de diâmetro por 18,5 cm de altura, preenchidos com areia lavada de rio. As profundidades de semeadura foram 0, 1, 2, 3 e 4 cm e as condicoes de luminosidade foram de 100% em viveiro a pleno sol, e de 50% em viveiro com cobertura de tela sombrite preta. Os ambientes, as profundidades e a interacao ambiente x profundidade afetaram a germinacao final do baru. A media de germinacao a 100% de luminosidade foi de 72,8%, e do ambiente com 50% de luminosidade foi de 52,5%. Similarmente, a germinacao media por semana foi de 17,1% e 11,1%, respectivamente. Logo, o ambiente a pleno sol foi o melhor para a germinacao das sementes. As profundidades de 1 a 3 cm proporcionaram a obtencao das melhores taxas de germinacao, que foram acima de 90% no ambiente a pleno sol, e em torno de 60% no ambiente com 50% de luminosidade. As melhores velocidades de germinacao foram tambem observadas nas profundidades de 1 a 3 cm. A interacao ocorreu de forma significativa a 0 cm, onde os indices de germinacao e de velocidade de germinacao, apenas a essa profundidade, foram superiores no ambiente a 50% de luminosidade. Portanto, para uma melhor e mais rapida germinacao, as sementes de baru devem ser plantadas entre 1 e 3 cm de profundidade em ambiente com 100% de luminosidade.

This study evaluated the use of a Fenton's reaction in a falling film solar reactor (FFR), as a possible advanced oxidation process for the mineralization of the organic compound phenol in water. Preliminary tests were carried out to evaluate phenol degradation by photolysis and to select the optimal residence time in which to carry out the process using a solar photo-Fenton system. The variables studied were the initial phenol concentration (100 to 300 mg L(-1)), the [Phenol]:[H2O2] mass ratio (1.0 to 2.0) and the [H2O2]/[Fe2+] molar ratio (5 to 10). Phenol degradation of 99% and chemical oxygen demand (COD) reduction of 97% were obtained under the following reaction conditions: phenol concentration=200 mg L(-1), mass ratio [Phenol]:[H2O2]=1.5 and molar ratio [H2O2]/[Fe2+]=7.5. Overall mineralization was achieved using the solar photo-Fenton process to destroy phenol and COD. The solar photo-Fenton process using a FFR appears to be a viable method for removing phenols in wastewaters on an industrial scale.

Abstract: Armored scale insects (Hemiptera: Diaspididae), are phytophagous species that occur in major biogeographic regions of the world. Because of the importance of diaspidids as pests, there is widespread interest in countries that export and import unprocessed agricultural products in increased knowledge of this group which includes invasive and quarantine pests of great economic concern. The diversity, geographic distribution, and host of diaspidids were studied from November 2002 to December 2018 in 34 municipalities in the state of Espírito Santo, Brazil. Forty species of Diaspididae from 27 genera were collected and identified. The species Acutaspis perseae (Comstock), A. umbonifera (Newstead), Aonidiella aurantii (Maskell), Comstockaspis perniciosa (Comstock), Lepidosaphes beckii (Newman), Lepidosaphes gloverii (Packard), Morganella longispina (Morgan), Mycetaspis apicata (Newstead), and Thysanofiorinia nephelii (Maskel) were found for the first time in Espírito Santo. The plant families Myrtaceae, Moraceae, Arecaceae, Asparagaceae, and Rutaceae had the greatest number of host plant species of armored scale. Fifty-seven new host associations were observed for 25 species of diaspidids and 11 diaspidid species were recorded for the first time from nine families of plants. Selenaspidus articulatus (Morgan) was the most polyphagous species observed with 17 host plant species from 12 families, followed by Pseudaonidia trilobitiformis (Green), and Parlatoria proteus (Curtis). With these new records, 41 species and 28 genera of Diaspididae have been recorded in Espírito Santo.

Foram estudados os efeitos de cinco profundidades de semeadura e duas condicoes de luminosidade na germinacao de sementes de mangaba. As sementes foram plantadas em vasos de plastico de 14 cm de diâmetro por 11 cm de altura, preenchidos com areia lavada de rio. As profundidades de semeadura foram 0, 1, 2, 3 e 4 cm e as condicoes de luminosidade foram de 100% em viveiro a pleno sol e de 50% em um viveiro com cobertura de tela sombrite preta. Apenas os diferentes ambientes afetaram a percentagem de germinacao e a percentagem de germinacao media por semana. A media de germinacao a 100% de luminosidade foi de 32,4%, superior a do ambiente com 50% de luminosidade, que foi de 8,4%. Similarmente, a germinacao media por semana foi de 7,02% e 1,97%, respectivamente. O numero medio de semanas necessarias para germinar foi melhor na profundidade de 0 cm com tempo de 4,06 semanas, diferindo significativamente das profundidades de 1, 2, 3 e 4 cm com tempos de 4,68, 5,34, 4,85 e 4,94 semanas, respectivamente. A germinacao da mangaba teve seu inicio na terceira semana, atingiu um pique na quinta semana a estabilizou-se na sexta semana apos a semeadura. Para uma melhor e mais rapida germinacao, as sementes de mangaba devem ser plantadas subsuperficialmente, proximo a 0 cm de profundidade, em ambiente com 100% de luminosidade.

Foram desenvolvidos estudos referentes a relacao entre area foliar (AF), comprimento (C) e largura (L) das folhas de mudas de mangabeira, crescidas em viveiros a pleno sol (100% de luminosidade) e coberto com tela sombrite (50% de luminosidade). As avaliacoes foram feitas pegando-se aleatoriamente uma muda de cada ambiente e cada epoca de avaliacao. As epocas avaliadas foram oito, sendo cada avaliacao feita a intervalos de cinco semanas. As folhas sem os peciolos foram numeradas e com uma regua milimetrada foram tomadas as medidas de comprimento e maior largura do limbo. A AF individual foi lida em um integrador Hayashi Denko Co. LTD, Modelo AAM-7. Relacoes de AF com C, L e C x L foram analisadas atraves de regressao. As diferencas ambientais entre os dois viveiros nao afetaram nenhuma das caracteristicas foliares avaliadas. Logo, apenas uma equacao para cada caracteristica foliar foi determinada: AF = 0,66 + 0,11 C + 0,32 CZ , AF = 1,44 - 1,74 L+1,97 LZ a AF = 0,76 C x L. A equacao linear AF = 0,76 C x L foi a que melhor se adequou ao modelo (Rz=0,989), proporcionando a obtencao de estimativas de AF mais rapidas e precisas.

New Schiff base compound N,N'-bis-(4-hexadecanate)-salicylethylenediamine (named IM) was synthesized, and characterized via infrared and nuclear magnetic ressonance spectroscopies. IM was tested as corrosion inhibitor and antioxidant in soybean biodiesel. Corrosion studies were developed with AISI 1020 carbon steel in a three-step accelerated corrosion assay and IM inhibitory activity was evaluated using microscopic techiniques: optical microscopy (OM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). In 750 ppm concentration, IM showed better inhibitory activity compared to commercial compounds tert-butylhydroquinone and pyrogallol, reducing root-mean-square roughness (Rq) from 37.8 to 11.7 nm and peak-peak height (PP) from 454.1 to 120.2 nm after 8 days of immersion. Antioxidant studies were conducted using the PetroOXY equipment. In 250 ppm concentration, IM showed better antioxidant activity as metal chelator, reducing biodiesel oxidation induced by copper on biodiesel. In this concentration, IM increased the induction period from 3.0 to 5.8 h. Furthermore, the new Schiff base acts as an oxygen scavanger. This is a great property because it reduces oxygen concentration in biodiesel, reducing metal corrosion reactions.

Para determinar a area foliar de mudas de cagaiteira em condicoes de viveiro a pleno sol e a 50% da radiacao solar incidente, foram relacionadas medidas lineares de comprimento (C), largura (L) e o produto do comprimento pela largura das folhas com suas respectivas areas foliares. Durante nove meses, a cada cinco semanas, escolhia-se aleatoriamente uma planta de cada ambiente, destacavam-se as folhas e mediam-se, com uma regua milimetrada, o comprimento e a maior largura do limbo, e, com um leitor optico Hayashi Denko Co, LTD, modelo AAM-7, a area foliar dos limbos, individualmente. Nao houve influencia dos ambientes sobre as caracteristicas foliares avaliadas. Portanto, foi determinada apenas uma equacao, independentemente do ambiente de crescimento, para cada uma dessas caracteristicas. As equacoes do comprimento (AF = -3,598 + 2,331 C) e a da maior largura (AF = - 3,444 + 4,913 L) obtidas tiveram um bom ajuste ao modelo linear (R 2 para comprimento = 0,844 a R 2 para largura = 0,836). Porem, o melhor ajuste ao modelo linear foi o da equacao do comprimento x largura (AF = 0,719 C x L com R 2 = 0,977).

ABSTRACT Around 20% of Brazilian coffee production corresponds to defective beans (PVA), which decreases the quality of the coffee brews. Steam treatment has been reported as an alternative to improve the cup quality of coffee products. This research aimed to study the feasibility of using steamed Robusta PVA beans in instant coffee products. After the steam treatment (2 bar for 3 min), the Robusta PVA was dried, roasted, subjected to extraction in a pilot plant, and freeze-dried. The steamed and untreated Robusta PVA materials (raw, roasted, and instant coffees) and blends of instant Arabica coffee with PVA were characterized. The steamed Robusta PVA instant coffee presented 7.01 g caffeine and 8.74 g total chlorogenic acids in 100 g product. Instant coffee blends with 30% and 50% of steamed Robusta PVA in Arabica coffee were studied. A sensory difference between blends with steamed and untreated Robusta PVA was only perceived by the addition of 50% PVA. The blend with 50% of steamed coffee was preferred and well accepted (average grade of 7.9 on a 10-scale). The use of steamed Robusta PVA coffee (under mild steam treatment conditions, 2 bar/3 min) in instant coffee was viable, and it was obtained an instant coffee to be used in a blend with 50% of Arabica coffee with a good profile of bioactive compounds and sensory acceptance.

The thermal requirements for development of Dermanyssus gallinae were studied under laboratory conditions at 15, 20, 25, 30 and 35 degrees C, a 12h photoperiod and 60-85% RH. The thermal requirements for D. gallinae were as follows. Preoviposition: base temperature 3.4 degrees C, thermal constant (k) 562.85 degree-hours, determination coefficient (R(2)) 0.59, regression equation: Y= -0.006035 + 0.001777x. Egg: base temperature 10.60 degrees C, thermal constant (k) 689.65 degree-hours, determination coefficient (R(2)) 0.94, regression equation: Y= -0.015367 + 0.001450x. Larva: base temperature 9.82 degrees C, thermal constant (k) 464.91 degree-hours, determination coefficient (R(2)) 0.87, regression equation: Y= -0.021123 + 0.002151x. Protonymph: base temperature 10.17 degrees C, thermal constant (k) 504.49 degree-hours, determination coefficient (R(2)) 0.90, regression equation: Y= -0.020152 + 0.001982x. Deutonymph: base temperature 11.80 degrees C, thermal constant (k) 501.11 degree-hours, determination coefficient (R(2)) 0.99, regression equation: Y= -0.023555 + 0.001996x. The results obtained showed that 15 to 42 generations of Dermanyssus gallinae may occur during the year in the State of São Paulo, as estimated based on isotherm charts. Dermanyssus gallinae may develop continually in the State of São Paulo, with a population decrease in the winter. There were differences between the developmental stages of D. gallinae in relation to thermal requirements.

In this study we analyzed data on fishing landings of Genidens barbus in the state of São Paulo, Brazil, from 2000 to 2014. An estimation of the total production was obtained through the analysis of 781,856 landings, among which 87% were categorized as artisanal and 13% as industrial. The abundance index showed some stability in the period. However, due to the high number of production units, the fishing effort need to be maintained, given that there is a risk that increased production might affect the abundance of G. barbus. Thus, as alternatives to maintaining marine catfish exploitation in southeastern Brazil under control, the following management actions can be suggested: i) prohibition of fishing activity by the industrial sector; ii) strengthening of inspection of the fleet that is not allowed to participate in the marine catfish fisheries, with emphasis on purse seiners; and iii) maintenance of a closed season for G. barbus, performing an adaptive management of fishing prohibition according to the reproductive biology of the species and with the support of artisanal fishers. These measures have the aim of promoting sustainable exploitation of G. barbus, especially through small-scale fisheries in southeastern Brazil.

Abstract To assess the bioequivalence of two zolpidem hemitartrate formulations in 30 healthy volunteers. Plasma samples were obtained over a 24 h period. Plasma concentrations of zolpidem were analyzed by liquid chromatography coupled to tandem mass spectrometry with positive ion electrospray ionization using multiple reaction monitoring. Values of peak concentration ( C max ), area under curve (AUC), half‐life, elimination constant, volume of distribution and clearance showed statistically significant differences when comparing women (604.34 ng h/ml, 127.36 ng/ml, 4.4 h, 0.18 1/h, 50.56 L and 8.55 L/h, respectively) and men (276.1 ng h/ml, 70.9 ng/ml, 3.3 h, 0.26 1/h, 91.42 L and 24.34 L/h, respectively), receiving the same dose (5 mg), respectively. The geometric means with corresponding 90% confidence interval for Test/Reference percentage ratios were 99.73% (CI 93.69–106.16) for C max, 97.44% (90% CI = 91.85–103.37%) for area under curve of plasma concentration until the last concentration observed (AUC last ) and 98.30% (90% CI = 92.48–104.49) for the area under curve between the first sample (pre‐dosage) and infinity (AUC 0–inf ). Since the 90% CI for AUC last , AUC 0–inf and C max ratios were within the 80–125% interval proposed by the US Food and Drug Administration, it was concluded that zolpidem hemitartrate formulation (5 mg orodispersible tablet) is bioequivalent to the zolpidem hemitartrate formulation (Patz SL 5 mg sublingual tablet) with regard to both the rate and the extent of absorption. A new formulation of zolpidem 2.5 mg may be useful in women for the same clinical benefits as the 5 mg formulation in men.

Resumo A soldagem de alto aporte térmico é uma alternativa que tem sido empregada na indústria naval e de petróleo para reduzir o número de passes de soldagem em estruturas espessas por meio do aumento da taxa de deposição. Isso tem levado desenvolvimento de aços e de consumíveis que permitem a obtenção de juntas com aceitável nível de tenacidade na zona termicamente afetada, mesmo com aportes térmicos muito elevados. Contudo, ainda não são muito claras as consequências do ponto de vista metalúrgico que este procedimento pode acarretar na zona fundida. O presente trabalho avalia a influência de aportes térmicos de até 17,1 kJ/mm na microestrutura e características mecânicas da zona fundida obtida na soldagem de um aço naval TMCP EH36 feita em único passe com o processo ao arco submerso multi-eletrodos e com adição de arame frio. A microestrutura foi comparada com a de soldas realizadas com energia menor e mapas de dureza foram produzidos e comparados, avaliando-se também a eficiência dos consumíveis geralmente aplicados para a soldagem e alto aporte. Foi observado que o teor de molibdênio na solda contribui de forma direta para a manutenção das propriedades mecânicas da zona fundida na soldagem de alto aporte térmico.

Este estudo teve como objetivo avaliar alguns impactos decorrentes do deslocamento miscível de efluente de nitração de uma indústria de explosivos aplicado em colunas de um Latossolo Amarelo, horizonte B (LA-B), submetido aos tratamentos: adição de carbonatos (BASE), ácidos (ACID), fosfato (FOSF), carbonatos e fosfato (BASE-FOSF) e ácidos e fosfatos (ACID-FOSF). A recuperação de nitrogênio em relação ao total aplicado varia entre 10,1 (ACID) e 65,5% (BASE). Há correlação significativa entre as curvas de transposição de N obtidas experimentalmente e as simuladas pelo aplicativo STANMOD para a maioria das colunas (p&lt;0,001). A exceção ocorreu para ACID-FOSF (p=0,202). Não há correlação entre carga eletrostática líquida (CEL) e as variáveis de ajuste do modelo: fator de retardamento (FR), coeficiente de dispersão-difusão (D) e taxa de decaimento de primeira ordem (µ). A adição de fosfato (FOSF) favorece a movimentação do nitrogênio, pois diminui FR (2,35±0,05) e µ (0,498±0,050 h-1) e aumenta D (41,8±5,5 cm² h-1) em relação ao observado na coluna LA-B (2,51±0,03; 1,697±0,084 h-1 e 2,8±1,3 cm² h-1 respectivamente). A adição de carbonatos e/ou fosfatos (BASE, BASE/FOSF e FOSF) resultou nos maiores valores máximos de demanda química de oxigênio (DQO MÁX). A pequena quantidade de DNA extraída das células bacterianas nos solos sugere que, possivelmente, os processos que governam a adsorção e movimentação de N sejam de natureza não biológica ou que a elevada DQO do líquido percolado prejudica os microrganismos do solo.

ABSTRACT: Post-harvest cotton stalk control is mandatory in many cotton producing countries, and the major methods used for this practice are mechanical and chemical (glyphosate and 2,4-D as the most usual herbicides applied), or a combination of both. However, the adoption of glyphosate-resistant cotton varieties by growers have required the development of alternative chemical treatments. Six trials were conducted to evaluate systems combining mowing and chemical control of glyphosate-resistant cotton stalks. Experiments conducted in 2014 were installed in randomized complete block design with nineteen treatments and four replicates. In 2015, the experiments were also conducted in randomized complete block design with eleven treatments and four replicates. Herbicide treatments were applied after cotton stalk mowing. Cotton stalk control varied according to rainfall regime after herbicide application. A single herbicide application to stub regrowth plants did not provide acceptable efficacy in cotton stalk destruction, independently of the treatment used. The best options for glyphosate-resistant cotton stalk control consisted of 2,4-D application immediately after mowing, followed by sequential application of combinations of 2,4-D with flumiclorac, carfentrazone or imazethapyr.