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The present study aimed to evaluate the Strata-X® sorbent, commonly used in cartridges, through analysis by high-performance liquid chromatography coupled with mass spectrometry. Due to the different physical-chemical characteristics of the compounds, different conditions of chromatography and mass analysis were necessary. The developed methods were validated in terms of selectivity, linear range, linearity (coefficient of determination, r2), the limit of detection (LOD), the limit of quantification (LOQ), accuracy (recovery, %), and precision (RSD, %). The results allowed us to select efficient extraction methods, using methanol acidified to pH 2 with formic acid, to elute the herbicides 2,4-D and dicamba in both sorbent materials. Besides, the Strata-X® sorbent was efficient in the sorption of analytes; thus, we indicate it for potential use in air sampling as an alternative to XAD-2.

Weeds represent an increasing challenge for crop systems since they have evolved adaptability to adverse environmental conditions, such as salinity stress. Herbicide effectiveness can be altered by the quality of water in which the weed is growing. This research aimed to study the combined effect of salt stress and recurrent selection with a sublethal dose of imidazolinone herbicides in the shifting of the sensitivity of Echinochloa colona (L.) Link (junglerice) to imidazolinone herbicides. This study was divided into two experiments, in experiment I, three recurrent selection cycles were conducted in Pelotas/RS/Brazil with imazapic + imazapyr at 0.125× the field rate, and in experiment II, three recurrent selection cycles were conducted in Fayetteville/AR/USA with imazethapyr, at 0.125× the recommended dose. Salt stress was implemented by irrigation with 120 mM sodium chloride (NaCl) solution. The effective dose for 50% control of the population (ED50) values increased from the field population to the second generation (G2) after recurrent selection with a sublethal dose of imidazolinone combined with salt stress, supporting the hypothesis of reduced susceptibility by the combination of these abiotic factors. Recurrent exposure to a sublethal dose of imazapic + imazapyr or imazethapyr, combined with salt stress, reduced susceptibility of Echinochloa colona (L.) plants to imidazolinone herbicides.

The use of imidazolinone-tolerant rice cultivars allows selective control of weedy rice and barnyardgrass. However, in many situations, there is a need to add herbicides from other chemical groups to increase the spectrum of weed control. In this sense, saflufenacil has the potential to be used in mixture with imidazolinone herbicides. This study aimed to evaluate the interaction effects of the imazapyr+imazapic and saflufenacil herbicides in weedy rice and barnyardgrass and to investigate their impacts on the yield of the irrigated rice cultivar Puitá INTA CL. To reach these aims, greenhouse and field experiments were carried out during two growing seasons, with herbicide treatments sprayed separately and in mixtures of saflufenacil with imazapyr+imazapic. Results showed that saflufenacil did not interfere with control of weedy rice and barnyardgrass obtained with imazapyr+imazapic. The D50 values of imazapyr+imazapic for weedy rice control were 14.5+5, 9.1+3 and 12.5+4.2 g ha-1of imazapyr+imazapic for combinations with 0, 3.06 and 6.12 g ha-1of saflufenacil, respectively. In the field experiments, all doses of imazapyr+imazapic applied isolated or in mixture with saflufenacil provided control levels barnyardgrass above 90% at 28 days after herbicides application. Furthermore, saflufenacil did not cause damage or loss in the yield of the rice crop when mixed with imazapyr+imazapic. The Puitá INTA CL rice cultivar was tolerant of the tested herbicides, whether applied alone or in mixture, reaching grain yield of 9.987 kg ha-1 when applied 42 g ha-1 of saflufenacil plus 147+49 g ha-1 of imazapyr+imazapic. RESUMO: A utilização de cultivares de arroz tolerantes às imidazolinonas possibilita um controle seletivo de arroz-daninho. No entanto, em muitas situações existe a necessidade de adição de herbicidas de outros grupos químicos para aumentar o espectro de controle de plantas daninhas. Neste sentido, saflufenacil apresenta potencial para ser utilizado em mistura com herbicidas imidazolinonas. Este estudo teve como objetivo avaliar os efeitos da interação dos herbicidas imazapyr+imazapic e saflufenacil em arroz-daninho e capim-arroz; e averiguar os impactos sobre a produtividade do cultivar de arroz irrigado Puitá INTA CL. Para alcançar esses objetivos, foram realizados experimentos em casa de vegetação e a campo em duas estações de cultivo, com os tratamentos herbicidas aplicados separadamente e em misturas de saflufenacil com imazapyr+imazapic. Os resultados mostraram que a adição de saflufenacil não interferiu no controle de arroz-daninho e capim-arroz obtido com imazapyr+imazapic. Os valores D50 de imazapyr+imazapic para o controle de arroz-daninho foram 14,5+5; 9,1+3 e 12,5+4,2 g ha-1 de imazapyr+imazapic para combinações com 0; 3,06 e 6,12 g ha-1 de saflufenacil. No experimento de campo todas doses de imazapyr+imazapic, aplicadas isoladas ou em mistura, proveram níveis de controle de capim-arroz superiores a 90% aos 28 dias após a aplicação dos herbicidas. Além disso, saflufenacil não causou injúrias ou perda de rendimento da cultura do arroz quando misturado com imazapyr+imazapic. O cultivar Puitá INTA CL foi tolerante aos herbicidas testados, sejam aplicados isolados ou em mistura, atingindo uma produtividade de 9.987 Kg ha-1 quando aplicado 42 g ha-1 de saflufenacil mais 147+49 g ha-1 de imazapyr+imazapic.

In this study, two fast methods, i.e., the dilute-and-shoot one and the solid-phase extraction (SPE) procedure, were evaluated for the determination of S-metolachlor and metolachlor-OA in runoff water samples by liquid chromatography tandem mass spectrometry (LC-MS/MS). The limits of quantification of both analytes were 2 μg L−1 and 0.02 μg L−1, by dilute-and-shoot and SPE, respectively. Good accuracy (86–114%) and precision (≤20%) were found. Besides, these methods were statistically similar. Thus, firstly, dilute-and-shoot is a promising alternative to analyzing samples with high levels of both analytes. Secondly, samples with low levels of both analytes can be submitted to SPE. Both methods were successfully employed, since they enabled the determination of S-metolachlor and metolachlor-OA in runoff water samples at concentrations between 0.082 and 267 μg L−1.

Changes in the environment, specifically rising temperature and increasing atmospheric carbon dioxide concentration [CO2], can alter the growth and physiology of weedy plants. These changes could alter herbicide efficacy, crop-weed interaction, and weed management. The objectives of this research were to quantify the effects of increased atmospheric [CO2] and temperature on absorption, translocation and efficacy of cyhalofop-butyl on multiple-resistant (MR) and susceptible (S) Echinochloa colona genotypes. E. colona, or junglerice, is a troublesome weed in rice and in agronomic and horticultural crops worldwide. Cyhalofop-butyl is a grass herbicide that selectively controls Echinochloa spp. in rice. Maximum 14C-cyhalofop-butyl absorption occurred at 120 h after herbicide treatment (HAT) with >97% of cyhalofop-butyl retained in the treated leaf regardless of [CO2], temperature, or genotype. Neither temperature nor [CO2] affected herbicide absorption into the leaf. The translocation of herbicide was slightly reduced in the MR plants vs. S plants either under elevated [CO2] or high temperature. Although plants grown under high [CO2] or high temperature were taller than those in ambient conditions, neither high [CO2] nor high temperature reduced the herbicide efficacy on susceptible plants. However, herbicide efficacy was reduced on MR plants grown under high [CO2] or high temperature about 50% compared to MR plants at ambient conditions. High [CO2] and high temperature increased the resistance level of MR E. colona to cyhalofop-butyl. To mitigate rapid resistance evolution under a changing climate, weed management practitioners must implement measures to reduce the herbicide selection pressure. These measures include reduction of weed population size through reduction of the soil seedbank, ensuring complete control of current infestations with multiple herbicide modes of action in mixture and in sequence, augmenting herbicides with mechanical control where possible, rotation with weed-competitive crops, use of weed-competitive cultivars, use of weed-suppressive cover crops, and other practices recommended for integrated weed management.

Global climate change, specifically rising temperature, can alter the molecular physiology of weedy plants. These changes affect herbicide efficacy and weed management. This research aimed to investigate the combined effect of heat stress (HS) and sublethal doses of herbicides (four active ingredients) on adaptive gene expression and efficacy of herbicide on Echinochloa colona (L.) Link (junglerice). Three factors were evaluated, factor A was E. colona generation (G0-original population from susceptible standard, G1 and G2 were progenies of recurrent selection), factor B was herbicide treatment (florpyrauxifen-benzyl, glufosinate-ammonium, imazethapyr, quinclorac and nontreated check) and factor C was HS (30 and 45 &deg, C). The herbicides were applied at 0.125&times, the recommended dose. Recurrent exposure to HS, combined with sublethal doses of herbicides, favors the selection of plants less susceptible to the herbicide. Upregulation of defense (antioxidant) genes (APX: Ascorbate peroxidase), herbicide detoxification genes (CYP450 family: Cytochrome P450), stress acclimation genes (HSP: Heat shock protein, TPP: Trehalose phosphate phosphatase and TPS: Trehalose phosphate synthase) and genes related to herbicide conjugation (UGT: UDP Glucosyltransferase) was significant. The positive regulation of these genes may promote increased tolerance of E. colona to these herbicides.

Echinochloa colona (junglerice) is a problematic global weed for many crops, primarily controlled with herbicides. Drought stress alters the overall plant physiology and reduces herbicide efficacy. This research aimed to study the joint effect of drought stress (DS) and recurrent selection with sublethal dose of herbicide on adaptive gene expression and herbicide efficacy on E. colona. Three factors were evaluated: (A) E. colona generation (G0, original population from susceptible standard, G1 and G2, progenies of recurrent selection), (B) herbicide treatment (florpyrauxifen-benzyl, 0.25&times, glyphosate, 0.125&times, quinclorac, 0.125&times, the recommended dose, and nontreated check), (C) DS (50% and 100% field capacity). Recurrent exposure to sublethal herbicide dose, combined with drought stress, favors the selection of plants less susceptible to the herbicide. Upregulation of defense (antioxidant) genes (APX: ascorbate peroxidase), herbicide detoxification genes (CYP450 family: cytochrome P450), stress acclimation genes (HSP: heat-shock protein, TPP: trehalose phosphate phosphatase, and TPS: trehalose phosphate synthase), and genes related to herbicide conjugation (UGT: UDP glucosyltransferase) in the G2 population was significant. Recurrent exposure to sublethal herbicide dose under drought stress reduces junglerice sensitivity to herbicide, seemingly due to &ldquo, imprinted&rdquo, upregulation of metabolic and protection genes in response to these stresses.

Background Saflufenacil dissipation in soils under different moisture conditions is not available in the scientific literature. The objective of this study was to evaluate saflufenacil degradation and persistence in soils from rice regions under field capacity (non-flooded) and saturated (flooded) conditions. Results The accelerated solvent extraction (ASE) residue analytical method developed to conduct the study resulted in recovery greater than 80% for the combinations of soils and moisture conditions. Saflufenacil degradation was faster at field capacity for all soils, except for Morey soil. Herbicide half-life was 28.6, 15.0 and 23.1 days under field capacity treatments and 58.8, 36.9 and 79.7 under saturated conditions for Nada, Crowley and Gilbert soils respectively. A half-life no longer than 80 days was observed for the combination of soils and moisture treatments. Conclusion An ASE method was developed and used to extract saflufenacil from soil samples. Half-life averaged among soils was 59 and 33 days for saturated and field capacity respectively. Saflufenacil persistence in the environment was 2–3 times longer under flooded conditions for most of the soils studied. © 2013 Society of Chemical Industry

Despite all advances obtained with the pesticide use worldwide and in Brazilian agriculture, there is still a lack of technologies for agricultural aircrafts. The objective of this study was to evaluate the drift produced by the use of conical nozzles and electrostatic system in aircraft application. The experimental design was completely randomized with a factorial arrangement and four replications. Treatments included two spraying equipment: electrostatic system with 5L ha-1 of spray volume and conical nozzle with 15 and 20L ha-1. In all treatments, azoxystrobin fungicide was used at a dose of 100g a.i. ha-1 and paraffinic mineral oil at a dose of 0.5% v.v. Volume median diameter (VMD) and droplet density were estimated using water sensitive paper. Evaluations of drift distance were performed with glass collectors distributed horizontally on the soil surface, 50m before the application band, at the application site and 12,5, 25, 50, 75, 100, 150, 200 and 300m after the application site, along the wind direction. Azoxystrobin concentration in glasses were quantified by UHPLC-MS/MS. Results indicated that the drift distance can reach more than 300 meters away from the application site, with variable concentrations according to the equipment used. Electrostatic system reduced drift when compared to hydraulic conical nozzles. RESUMO: Apesar dos avanços obtidos no uso de agrotóxicos na agricultura mundial e brasileira, ainda existe carência em tecnologias voltadas para aviação agrícola. O objetivo deste estudo foi avaliar a deriva ocorrida com a utilização de bicos hidráulicos com pontas cônicas e sistema eletrostático em aplicação aérea. O delineamento experimental adotado foi inteiramente casualizado com quatro repetições. Os tratamentos foram compostos por dois equipamentos de pulverização: sistema eletrostático com volume de aplicação de 5L ha-1 e bicos hidráulicos com pontas cônicas, utilizando volumes de aplicação de 15 e 20L ha-1. Em todos os tratamentos, foi utilizado o fungicida azoxistrobina na dose de 100g i.a. ha-1 e óleo mineral parafínico na dose de 0,5% v.v. As avaliações de diâmetro mediano volumétrico e densidade de gotas foram realizadas através de papéis hidrossensíveis na faixa de aplicação. As avaliações de distância de deriva foram realizadas com coletores de vidro distribuídos horizontalmente sobre a superfície do solo, 50m antes da faixa, na faixa de aplicação e aos 12,5, 25, 50, 75, 100, 150, 200 e 300m após a faixa de aplicação, no sentido da direção de vento. Azoxistrobina foi quantificada por UHPLC-MS/MS. Os resultados indicam que a distância de deriva pode alcançar mais de 300 metros do local de aplicação, com concentrações variáveis de acordo com o equipamento utilizado. O sistema eletrostático reduz a deriva, quando comparado aos bicos hidráulicos com pontas cônicas.

O clorofilômetro e a cartela de cores têm sido utilizados para monitorar a adubação nitrogenada em diferentes culturas, com o pressuposto de que há uma relação entre suas leituras e o teor de nitrogênio (N) no tecido das plantas. O objetivo deste trabalho foi avaliar a utilização do clorofilômetro e da cartela de cores na estimativa do teor de N em folhas de arroz irrigado por alagamento. Foram utilizados dois experimentos instalados em um Planossolo Háplico, sendo o primeiro conduzido com cinco doses de N (0, 50, 80, 120 e 160kg ha-1 na forma de ureia) e a cultivar 'IRGA 417', e o segundo com seis cultivares de arroz irrigado de diferentes ciclos ('BR-IRGA 409', 'BR-IRGA 410', 'IRGA 417', 'IRGA 421', 'EPAGRI 108' e 'HÍBRIDO 2') com uma única dose de N. Foram realizadas avaliações com clorofilômetro e a cartela de cores nas folhas do arroz em diferentes épocas. Simultaneamente às leituras, foram coletadas amostras de folhas e nelas determinado o teor de N. Quando variaram as doses de N, houve correlação significativa entre as leituras do clorofilômetro e da cartela de cores com o teor de N nas folhas, independente da época de avaliação. Já quando variaram as cultivares, as leituras do clorofilômetro se correlacionaram com o teor de N (r=0,78; P

The algae Botryococcus braunii, one of the potential renewable resources for production of liquid hydrocarbons, was used for testing the effect of selected herbicides on algal growth and hydrocarbon content. Twenty-two herbicides representing 14 modes of action were assayed. Accelerated solvent extraction (ASE) was used to extract hydrocarbon from algae and the results showed that ASE was an efficient method for algal hydrocarbon extraction at 50 °C extraction temperature, 10.3 MPa of pressure and 1 static cycle using n-hexane as extraction solvent. The photosystem II inhibitor diuron was the most toxic herbicide for algal growth, but hydrocarbon content increased from 34.9 to 42.4% of dry biomass in the presence of a 0.1 mg/L concentration of diuron. The photosystem I inhibitor diquat was inhibitory to growth of B. braunii, but hydrocarbon content increased to 43.3% of dry biomass when treated with 5 mg/L diquat. S-metalochlor, a mitosis inhibitor, reduced both algal growth and hydrocarbon content. Hydrocarbon content decreased to 16.4, 14.0 and 5.5% of dry biomass, respectively when treated with 0.1, 1, and 5 mg/L S-metalochlor. The carotenoid biosynthesis inhibitor fluridone did not affect algal growth at 0.1 mg/L, but decreased hydrocarbon content from 34.9 to 13.2%. The fatty acid and lipid biosynthesis inhibitor thiobencarb had no effect on algal growth or hydrocarbon content at 0.1 mg/L, but it inhibited algal growth and decreased hydrocarbon content from 34.9 to 7.8% at 1 mg/L. The oxidative phosphorylation uncoupler dinoterb at 0.1 mg/L reduced algal biomass by 52.8% and decreased hydrocarbon content from 34.9 to 30.0%. The use of B. braunii as a source of fuel will undoubtedly require the use of an outdoor open pond system. These results will be useful for improving algal oil production while developing management systems to control invasive algal species in outdoor open pond systems ultimately keeping the oil producing algae pure.

Saflufenacil is a new herbicide for broadleaf weed control in various crops. In rice, saflufenacil can be a prospective combination partner to complement the broadleaf weed control of herbicides such as imazethapyr. This study was established to evaluate 1) rice tolerance and 2) weed control of red rice (Oryza sativa L.) and hemp sesbania (Sesbania exaltata P. Mill.) to saflufenacil tank-mixed with imazethapyr. The experiment was conducted during 2009 and 2010 at the Texas A&M AgriLife Research and Extension Center located at Beaumont, TX. Treatments included a check, an imazethapyr treatment alone (70 g a.i. ha−1 at the 1- to 2-leaf stage (EPOST) plus 70 g a.i. ha−1 at the 4- to 6-leaf stage (LPOST)), and four saflufenacil doses (12.5, 18.75, 25, and 50 g a.i. ha−1) applied at EPOST and LPOST. Imazethapyr treatment was applied to all saflufenacil treatments. Rice injury increased with doses of saflufenacil and injury up to 83% was observed at 7 DAA when 50 g ha−1 was applied EPOST. Subsequent evaluations indicated less injury over time demonstrating rice recovery from saflufenacil treatments. No injury was observed in the imazethapyr treatment alone. Rice plants seemed to recover faster from LPOST application injury than EPOST. Hemp sesbania control was ≥88% in all saflufenacil treatments in evaluations conducted before harvest indicating effective control throughout the growing season. Red rice control was 100% for all treated plots containing imazethapyr in both years. Therefore, imazethapyr control of red rice was not adversely affected by tank-mixing with saflufenacil. Although injury was significantly higher in the highest doses of saflufenacil, rice yield was not adversely altered by the herbicide treatments. In summary, rice was injured at the highest doses of saflufenacil, but injury did not reduce rice yield. Hemp sesbania was effectively controlled by saflufenacil (>90% on average). No antagonistic interactions between saflufenacil and imazethapyr were observed with red rice control. Saflufenacil appears to be an effective herbicide candidate for broadleaf control in rice.

This research was conducted to evaluate (1) rice tolerance to saflufenacil applied preemergence (PRE) and postemergence (POST) and (2) the combination of saflufenacil and clomazone in light-textured soils. No injury from PRE application of saflufenacil was observed in 2009, and minimal injury for saflufenacil alone was observed in 2010. Injury as high as 68% was observed with combinations of 505 g ha−1of clomazone applied PRE and 50 g ha−1of saflufenacil applied POST in 2009 early evaluations. No interaction between clomazone and POST saflufenacil rates was observed in 2010. Rice injury intensified with increasing rates of saflufenacil applied POST. However, rice recovered with time for herbicide treatments applied PRE and POST in both years. Consequently, rice yield was not affected by any of the saflufenacil rates applied either PRE or POST in a clomazone weed control program.

Irrigated rice production can involve environmental contamination with pesticides due to the proximity of the fields to rivers and to management problems. During three years (2000 to 2003) the rice herbicides clomazone, propanil and quinclorac were quantified in water during the rice growing season, in the Vacacaí and Vacacaí-Mirim Rivers, located in Rio Grande do Sul (RS) State, Brazil. Water samples were taken at several locations in each river, selected by their importance in terms of rice drainage area. The samples were analyzed by HPLC-UV. At least one herbicide was detected in 41% of the samples from the Vacacaí River and 33% from the Vacacaí-Mirim River. The most frequent herbicide in both rivers and in each year was clomazone. The amount of herbicides in the river water was dependent on the rainfall regime. River water contamination by rice herbicides is probably caused by the rice water management used in the fields. The maintenance of flooded areas makes herbicides prone to contaminate the environment. To reduce the environmental contamination risk it is necessary to adopt measures to avoid overflow of flooded rice fields, keeping paddy water in the field for time enough to reduce the herbicide concentration before its release and enhancing the quality of the levees to reduce the probability of paddy rice overflow.

Além do impacto ambiental, a deriva de glyphosate pode causar danos sobre culturas sensíveis a esse herbicida. O objetivo deste estudo foi avaliar a influência de adjuvantes e pontas de pulverização na deriva de glyphosate aplicado via terrestre. O estudo foi conduzido em campo, arranjado em esquema fatorial (3 x 9), sendo o primeiro fator constituído por três pontas de pulverização: uma de jato plano (Teejet XR 110.015) e duas de jato plano com indução de ar (Teejet AIXR 110.015 e Teejet TTI 110.015). O segundo fator foi composto por sete adjuvantes: Break Thru(r) (0,1% v.v.), Grap' Oil(r) (0,5% v.v.), Grap Super Gun(r) (0,03% v.v.), Iharol(r) (1% v.v.), NP-10(r) (0,075 L ha-1), Dash HC(r) (0,5% v.v.) e Emultec R(r) (0,05 L ha-1). Os adjuvantes foram adicionados à calda de aplicação juntamente com o herbicida Roundup Transorb R(r) na dose de 2,16 kg e.a. ha-1. Além desses, foram incluídos dois tratamentos testemunha: um sem aplicação e outro com aplicação de glyphosate sem adjuvante. As variáveis avaliadas foram a distância percorrida pelas gotas para fora do alvo, a fitotoxicidade causada pela deriva, o diâmetro mediano volumétrico, a densidade de gotas e o volume recuperado pela utilização de papéis hidrossensíveis. As pontas de pulverização TTI 110.015 e AIXR 110.015 proporcionaram menor deriva que a ponta XR 110.015. As pontas TTI e AIXR apresentaram menor densidade de gotas e maior diâmetro mediano volumétrico, quando comparadas à ponta XR. A utilização dos adjuvantes NP-10(r) e Emultec R(r) com a ponta de pulverização XR 110.015 aumentou a deriva quando comparada com a aplicação de glyphosate sem adjuvante, porém não diferiram dos demais adjuvantes. O adjuvante Emultec R(r) aumentou o DMV das gotas, quando geradas pela ponta XR 110.015. A utilização dos adjuvantes Grap' Oil(r), Grap Super Gun(r), Iharol(r) e Dash HC(r) diminuiu a densidade de gotas derivadas, quando geradas pela ponta XR 110.015. Glyphosate drift can cause environmental impact and also affect crops that are sensitive to this herbicide. The aim of this study was to evaluate the influence of different adjuvants and different nozzles on glyphosate drift in terrestrial applications. The study was conducted in the field, arranged in a factorial design (3 x 9): factor A consisted of three different spray nozzles: one flat spray nozzle (Teejet = XR 110.015) and two air induction flat spray nozzles (Teejet AIXR 110.015 and Teejet TTI 110.015). Factor B was composed of seven adjuvants: Break Thru(r) (0.1% v.v.), Grap' Oil(r) (0.5% v.v.), Grap Super Gun(r) (0.03% v.v.), Iharol(r) (1% v.v.), NP-10(r) (0.075 L ha-1), Dash HC(r) (0.5% v.v.) and Emultec R(r) (0.05 L ha-1). The adjuvants were added to Roundup Transorb R(r) herbicide at 2.16 a.i. ha-1. Moreover, there were two control treatments, one untreated check and another one with application of glyphosate without adjuvant. The distance of droplets off-target, injury caused by drift, volumetric median diameter (VMD), droplet density and volume were evaluated by water sensitive paper cards. The TTI 110.015 spray nozzle resulted in lesser drift when compared to the AIXR 110.015 and XR 110.015 nozzles. The TTI and AIXR nozzles showed lower droplet density and greater VMD compared with the XR nozzle. The use of NP-10(r) and Emultec R(r) adjuvants with spray nozzle XR 110.015 increases drift. Adjuvant Emultec R(r) increases VMD droplets when used with the XR 110.015 nozzle. The use of adjuvants Grap' Oil(r), Grap Super Gun(r), Iharol(r) and Dash HC(r) decrease density derived droplets when generated with the XR 110.015 nozzle.

Thiamethoxam and chlorantraniliprole insecticides have been important tools for controlling pests in rice. However, food safety issues related to pesticide residues are important to consider with a food crop such as rice. Therefore, the objective of this study was to analyze thiamethoxam and chlorantraniliprole residues in rice hull, bran, and polished rice grains. The study was conducted during the 2012 cropping season at the Texas AM Agrilife Research, David R. Wintermann Rice Research Station, near Eagle Lake, TX, USA. Rice was planted on May 5, 2012, using the cultivar 'Presidio'. Pesticide applications were performed at 5, 15, 25, and 35 days after flowering (DAF) using 1 and 2 times the recommended rate of 30 g active ingredient (ai) ha(-1) for thiamethoxam and 30 g ai ha(-1) for chlorantraniliprole. Sequentially, two treatments using the insecticides at recommended rate were applied at 5 and 25 DAF and at 5, 25, and 35 DAF. Insecticide residues were analyzed in different sample fractions: rice hull, bran, and polished rice grains. The samples were subjected to extraction using an accelerated solvent extraction (ASE) technique. Sample aliquots were analyzed using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), with a limit of quantification (LOQ) of 5 × 10(-5) mg kg(-1). Residues of thiamethoxam and chlorantraniliprole were detected in rice hull, bran, and polished rice grains, and the quantified values were greater in hull and in rice bran.

Após várias décadas de busca de alternativas para controle do arroz-vermelho, desenvolveram-se genótipos de arroz tolerantes a herbicida do grupo químico das imidazolinonas, o qual controla eficientemente esta planta daninha no Sistema Clearfield. O experimento teve como objetivo avaliar: a eficiência do controle de arroz-vermelho com a mistura formulada dos herbicidas imazethapyr (75 g L-1) + imazapic (25 g L-1) (produto comercial Only®); o residual do herbicida no solo através dos danos causados ao azevém e arroz não-tolerante; e a taxa de ocorrência de cruzamento natural entre o arroz-vermelho e o arroz cultivado. O delineamento experimental foi de blocos ao acaso, com três tratamentos e doze repetições. Para determinar o fluxo gênico entre o arroz tolerante a imidazolinonas e o arroz-vermelho, foram coletadas e analisadas as panículas de arroz-vermelho não-controladas. O efeito residual do herbicida em culturas não-tolerantes foi verificado através de coleta de fitomassa de azevém e do estande inicial do cultivar de arroz não-tolerante semeado no ano seguinte. O herbicida testado controlou eficientemente o arroz-vermelho e a fitotoxicidade inicial não reduziu a produtividade do cultivar tolerante. O estande inicial do cultivar IRGA 417 foi afetado pelo residual do herbicida no solo. Os resultados mostraram também que ocorre cruzamento natural entre o arroz-vermelho e o arroz cultivado, e a taxa obtida no experimento foi de 0,065%.

Extreme rainfall events are expected to be more frequent with the climate change, increasing the chances of prolonged flooding in rice producing areas. Therefore, it is important to understand the response of rice plants to flooding events that would result in plant submersion and it is interaction with herbicide applications. To achieve the objectives two studies were conducted in Southern Brazil (Pelotas, RS). Experiment 1 was conducted with ten rice cultivars and six submersion periods (one, five, seven, 15 e 20 days of plant submersion plus a check treatment. In the check treatment plants were keep under a flooding regime (water layer of 10 cm).). Experiment 2 was conducted with two cultivars, two water regimes (flooded and submerged) and six herbicides (clomazone, bispyribac sodium, penoxsulam, imazethapyr + imazapic, imazapyr + imazapic and an untreated check). Shoot dry matter, chlorophyll levels, total carotenoids, total phenolic content, levels of hydrogen peroxide and activity of catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) were assessed in plant samples. The results observed in the first experiment showed that cultivars Puita INTA CL, IRGA 417 and IRGA 422 CL were the most tolerant to submergence. The most susceptible cultivars were IRGA 424, BRS Querencia, EPAGRI 108 and BRS Taim. In general, the cultivar Puita INTA CL has lower oxidative damage than BRS Querencia when submerged. In order to cope with excessive free radicals, BRS Querencia demonstrated higher activity of SOD, APX and CAT enzymes compared to cultivar Puita INTA CL. Imidazolinone formulated mixtures of herbicides imazethapyr + imazapic and imazapyr + imazapic caused greater reduction in total chlorophyll content and carotenoids.

BACKGROUND: Saflufenacil is a broadleaf herbicide for preplant burndown and pre-emergence applications in various crops. This study was established to evaluate the absorption and translocation of saflufenacil in hemp sesbania and imazethapyr in red rice as a function of their post-emergence interaction and light intensity. RESULTS: Imazethapyr plus saflufenacil provided a greater uptake (30%) and translocation (35%) of 14C-imazethapyr than imazethapyr alone. In the section above treated leaf (ATL), a higher percentage of the absorbed imazethapyr (23%) was quantified in the imazethapyr plus saflufenacil treatment after 168 h. Faster basipetal movement of imazethapyr was identified under higher light availability. Absorption of 14C-saflufenacil ranged from approximately 40 to 60% among herbicide and light intensity treatments. At 12 and 24 h after treatment (HAT) a greater percentage (15–20%) of the absorbed saflufenacil was quantified above the treated leaf at the two lower light intensities. Similar trends were observed for basipetal movement of saflufenacil. CONCLUSION: Saflufenacil enhanced absorption, overall translocation and acropetal movement of imazethapyr in the TX4 red rice. Basipetal movement of imazethapyr was faster under higher light intensities. Overall, imazethapyr improved absorption of saflufenacil in hemp sesbania plants. Reduction in light intensity resulted in greater translocation of saflufenacil, promoting acropetal and basipetal distribution at the two lower light intensity treatments. Copyright © 2011 Society of Chemical Industry

Sublethal adverse effects may result from exposure of aquatic organisms to insecticides at environmentally relevant concentrations. Fingerlings of the common carp (Cyprinus carpio, Linnaeus, 1758), grass carp (Ctenopharyngodon idella, Valenciennes, 1844), and bighead carp (Aristichthys nobilis, Richardson, 1845) were exposed to diafuran, an insecticide widely used during rice cultivation in Southern Brazil. The aim of this study was to verify the relationship between the lethal concentration (LC50) of diafuran and the acetylcholinesterase (AChE) activity in brain and muscle tissues of these species as a possible early biomarker of exposure to this insecticide. LC50 was determined for fish exposed to diafuran concentrations during 96 h (short term): common carp: control, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mg L-1; grass carp: control, 1.0, 2.0, 3.0 and 3.5 mg L-1 and, bighead carp: control, 0.5, 1.0, 1.5, 2.0, 3.0 and 4.0 mg L-1, as well as the determination of AChE at concentrations near LC50 for these species. LC50 values (nominal concentrations) were 1.81 mg L-1 for the common carp, 2.71 mg L-1 for the grass carp and, 2.37 mg L-1 for the bighead carp. All carps exposed to diafuran were lethargic (lower concentrations) or immobile. Diafuran inhibited the acetylcholinesterase activity in brain (~38%) and muscle (~50%) of all species. Muscle of bighead carp under control treatment showed higher specific AChE activity than brain (14.44 against 5.94 µmol min-1 g protein-1, respectively). Concentrations of diafuran used for rice cropping may affect Cyprinus carpio, Ctenopharyngodon idella and Aristichthys nobilis behaviors and the AChE activities in brain and muscle of these species may be an early biomarker of toxicity of this insecticide. Exposição a inseticidas em concentrações elevadas no ambiente podem ocasionar efeitos adversos subletais em organismos aquáticos. Alevinos de carpa húngara (Cyprinus carpio, Linnaeus, 1758), carpa capim (Ctenopharyngodon idella, Valenciennes, 1844) e carpa cabeça grande (Aristichthys nobilis, Richardson, 1845) foram expostos ao diafuran, um inseticida utilizado na cultura do arroz no sul do Brasil. O objetivo deste estudo foi verificar a relação entre concentração letal mediana (CL50) do diafuran e a atividade da enzima acetilcolinesterase (AChE) em cérebro e músculo dessas espécies, como um possível biomarcador inicial da exposição a este inseticida. A CL50 foi determinada com peixes expostos a concentrações de diafuran em 96 h: carpa húngara: controle; 0,5; 1,0; 1,5; 2,0; 2,5 e 3,0 mg L-1; carpa capim: controle; 1,0; 2,0; 3,0 e 3,5 mg L-1 e carpa cabeça grande: controle; 0,5; 1,0; 1,5; 2,0; 3,0 e 4,0 mg L-1, bem como a determinação da AChE em concentrações próximas da CL50 para essas espécies. Valores de CL50 (concentrações nominais) foram de 1,81 mg L-1 para carpa húngara, 2,71 mg L-1 para carpa capim e 2,37 mg L-1 para carpa cabeça grande. Todas as carpas expostas ao diafuran estavam letárgicas (menores concentrações) ou imóveis. Diafuran inibiu significativamente a atividade da AChE em cérebro (~38 %) e músculo (~50 %) de todas as espécies estudadas. Atividade da AChE em músculo para carpa cabeça grande foi mais alta que cérebro (14,44 contra 5,94 µmol min-1 g proteína-1, respectivamente). Este estudo demonstrou que concentrações de diafuran utilizadas na cultura do arroz podem afetar o comportamento de Cyprinus carpio, Ctenopharyngodon idella e Aristichthys nobilis, e a atividade da acetilcolinesterase cerebral e muscular pode ser um biomarcador inicial de toxicidade deste inseticida.

Este trabalho foi conduzido com o objetivo de avaliar a sobrevivência de alevinos de carpas expostas a carbofuran, metsulfuron-metílico e azimsulfuron em rizipiscicultura, bem como a produção de arroz irrigado e peixes. Foram utilizados alevinos de carpas húngara, capim e cabeça grande expostos aos agroquímicos em sistema pré-germinado de produção de arroz com manejo adequado de lâmina de água contínua durante os anos agrícolas de 2003/04 e 2004/05. O delineamento experimental foi de blocos ao acaso com oito tratamentos e quatro repetições, associando carpas sob a presença ou ausência de agroquímicos. Sete dias após a aplicação dos agroquímicos os alevinos de carpas foram colocados na área e foi verificado que os agroquímicos não afetam a sobrevivência destes. Devido a utilização de lâmina contínua de água no sistema a produção de grãos de arroz não foi afetada pela utilização de agroquímicos.

The long temporal persistence of select herbicides negatively impacts crops sown in succession to irrigated rice. One way to reduce these compounds in the soil over time is through phytoremediation. However, elevated CO2 concentrations may interfere with the phytoremediation process. Another consequence of climate change is the production of allelopathic compounds by forage species used as remedial agents. This study aimed to evaluate the impact of elevated CO2 concentration and drought stress on the remediation of soil samples contaminated with imazapyr + imazapic herbicides by Italian ryegrass and any subsequential affect on the allelopathic effect of this species. We report that the increasing CO2 decreased the phytoremediation potential of ryegrass. Water stress combined with a CO2 concentration of 700 µmol mol-1 caused increased allelopathy. Overall, these are the first data to indicate a significant effect of higher CO2 levels with respect to both phytoremediation efficacy and allelopathic potential of the plant species used in phytoremediation. RESUMO: O residual prolongado dos herbicidas do grupo das imidazolinonas é um problema para as culturas semeadas em sucessão ao arroz irrigado. Uma maneira de reduzir a concentração destes compostos no solo é utilizando a fitorremediação. Contudo, o aumento da concentração de CO2, pode interferir no processo de fitorremediação de plantas. Outra consequência que pode ser causada pelas mudanças climáticas é a produção de compostos alelopáticos das espécies forrageiras utilizadas como remediadoras. O presente estudo teve por objetivos quantificar se há perda no capacidade do azevém semeado em solo com residual de imazapir+imazapic de remediado quando submetido ao aumento da concentração de CO2 na atmosfera, combinada com estresse hídrico e alta população. A combinação do estresse hídrico com a concentração de CO2 de 700 µmol mol-1 causa aumento da alelopatia do azevém. De maneira geral, esses são os primeiros resultados que indicam o efeito significativo do aumento dos níveis de CO2 com relação à eficácia de remediação e de alelopatia de plantas usadas para fitorremediação.