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The herbicides indaziflam and amicarbazone effectively control weeds, as they persist for long extensions in the soil. The objective of this work was to evaluate the residual effect of indaziflam and amicarbazone in contrasting textures. Two experiments were conducted, one experiment for each herbicide using a the randomized block design, with four replications, in a 2x6+1 factorial scheme, that is, two types of soils, six application times (0, 20, 40, 60, 80 and 100 days after application - DAA) and a control. Used as doses of 100 and 1.400 g ha-1, for indaziflam and amicarbazone, respectively. At each evaluation period, the cucumber (Cucumis sativus L.) was sown and the visual intoxication of the species was measured at 21 days after sowing. At 0, 20 and 40 DAA of amicarbazone, phytointoxication was 100% for both soils. It was observed at 100 DAA, ditostically reducing phytointoxication, close to 0%, in sandy soil (DT50 @ 56 days) and 30% in clayey soil (DT50 @ 59 days). Indaziflam provided 100% phytointoxication at all times. It was concluded that the indaziflam had greater residual activity than amicarbazone, regardless of the soil. Already, for the amicarbazone, the effect was higher on the clay texture.

O tomate é uma olerícola que apresenta baixa tolerância à maioria dos herbicidas recomendados, fato que limita a utilização de produtos químicos no manejo integrado de plantas daninhas. Assim, o objetivo deste trabalho foi avaliar a eficácia e a seletividade do metribuzin e diuron, aplicados na modalidade pré-transplantio do tomate cultivado sobre diferentes coberturas vegetais. As sementes de tomate cv. IPA 6 foram semeadas em bandejas e transplantadas para os vasos no estádio de duas folhas verdadeiras. As coberturas usadas foram: solo exposto (controle), Urochloa ruziziensis (0,30 t ha-1), Pennisetum glaucum (0,42 t ha-1) e comunidade infestante (0,39 t ha-1), acondicionadas nos vasos antes da aplicação dos herbicidas. A fitotoxicidade dos herbicidas, a altura de plantas e a eficácia dos mesmos foram avaliadas aos 7, 14, 21, 28 e 35 dias após a aplicação (DAA), sendo que no último dia de avaliação também foi mensurada a massa seca de folhas, caule e raízes. Quanto à seletividade, o metribuzin proporcionou injúrias leves de fitointoxicação nas mudas, porém sem refletir em perdas na biomassa seca. Apesar da eficácia, o diuron não foi seletivo ao tomate, causando altos percentuais de fitointoxicação (65 a 100%). Conclui-se que a cobertura do solo com U. ruziziensis, P. glaucum e comunidade infestante complementou a ação de ambos os herbicidas, mas apenas o metribuzin foi seletivo quando aplicado em pré-transplantio do tomate.

O Paspalum virgatum L. é uma planta daninha comum de pastagens e possui difícil controle, principalmente devido sua semelhança com as forrageiras. As técnicas convencionais como gradagem e replantio da pastagem têm sido insatisfatórias no controle desta planta daninha. O objetivo deste trabalho foi avaliar o controle do capim-navalha (P. virgatum L.) à atrazine aplicada em pré-emergência, por meio de curva dose-resposta e a seletividade deste herbicida nas pastagens de Brachiaria brizantha cv. Marandu e Panicum maximum cv. Mombaça. Foram realizados três experimentos independentes, com cada espécie, em dois tipos de solo (Latossolo Vermelho Amarelo distrófico - LVAd de textura franco-argilosa e Argissolo Vermelho Amarelo distrófico - PVAd de textura franca), utilizando a escala percentual de notas para verificar o controle do capim-navalha e a fitotoxicidade nas forrageiras e massa seca no final dos experimentos. A atrazine controlou o capim-navalha, desde os 15 dias após a aplicação (DAA), nas doses abaixo da recomendação do fabricante (250 e 500 g ha-1 i.a.). Contudo, apesar dos sintomas de fitotoxicidade causados pela atrazine, houve retomada de crescimento aos 60 DAA tanto para B. brizantha cv. Marandu quanto para P. maximum cv. Mombaça. Houve menor fitotoxicidade às pastagens no solo de textura franco‑argilosa em relação ao solo de textura franca. A atrazine proporcionou controle eficiente do P. virgatum L. (500 g ha-1 i.a.) quando aplicada em pré-emergência e seletividade para B. brizantha cv. Marandu (

A aplicação de biochar (biocarvão) em solos por causa dos efeitos benéficos é comprovada por muitos pesquisadores internacionais e isto pode aumentar a sorção dos herbicidas e reduzir a eficácia destes no manejo das plantas daninhas. Impactos positivos são relatados em relação ao comportamento ambiental dos herbicidas, pois o aumento da sorção reduz a lixiviação destes produtos para as águas subterrâneas. Impactos negativos são relatados em relação ao manejo agronômico dos herbicidas, pois o aumento da sorção reduz a disponibilidade destes produtos no solo, diminuindo o efeito residual para o controle das plantas daninhas. No Brasil, o biochar é produzido por várias empresas privadas e unidades de pirólise, entretanto, o custo para produção ainda é muito alto, provavelmente por falta de incentivo do governo, baixo uso dos produtores e consciência dos benefícios. Embora o biochar seja utilizado há várias décadas em outros países, no Brasil ainda há poucos estudos desenvolvidos por pesquisadores na área de solos, e a eficiência do biochar na biodisponibilidade de herbicidas no solo ainda é desconhecida por muitos pesquisadores brasileiros na área de plantas daninhas. Diante do exposto, o objetivo desta revisão foi avaliar a biodisponibilidade de herbicidas em solos modificados com biochar e destacar a pesquisa com biochar em condições brasileiras, além de apresentar os benefícios ao solo com a adição do biochar. Pouco se sabe sobre o comportamento de herbicidas em solos brasileiros modificados com biochar, que pode ser utilizado com maior intensidade na agricultura moderna. Então, mais pesquisas são necessárias sob nossas condições para realmente entender a dinâmica deste produto no solo.

Para manter a qualidade da fibra do algodão, bem como proporcionar ótimos rendimentos na colheita, alguns aspectos devem ser levados em consideração como, por exemplo, a uniformidade dos capulhos e a desfolha, desta forma, a utilização de herbicidas e maturadores tornam-se imprescindíveis. Assim, o objetivo deste trabalho foi avaliar a eficiência do prohexadione-calcium quando aplicado isoladamente e em associação com outros produtos, na uniformização e abertura dos capulhos do algodão, assim como o efeito na desfolha e rebrota da cultura. Para tanto, conduziu-se um experimento de campo no município de Diamantino-MT. Adotou-se o delineamento de blocos casualizados, com quatro repetições e treze tratamentos, sendo estes compostos por: testemunha sem aplicação; prohexadione-calcium + ethefon + cyclanilide; prohexadione-calcium + flumiclorac-pentyl; prohexadione-calcium + diuron + thidiazuron; prohexadione-calcium + pyraflufen-ethyl; prohexadione-calcium; prohexadione-calcium + iharol. Os tratamentos foram aplicados quando aproximadamente 85% das maçãs da cultivar 975 WS estavam abertas. As variáveis: abertura das maçãs, rebrota e desfolha foram analisadas aos 0, 3, 6, 10 e 15 dias após a aplicação (DAA), e por fim, determinou-se a produtividade do algodão em caroço. Independente da dose, as plantas que receberam prohexadione-calcium associado à ethefon + cyclanilide, diuron + thidiazuron e pyraflufen-ethyl apresentaram maior número de maçãs abertas e maior desfolha. Conclui-se que os diferentes tratamentos químicos não proporcionaram diferenças estatísticas com relação a rebrota do algodão antes da colheita, aos 15 DAA, e que a utilização de prohexadione-calcium, isolado ou em associação com outros produtos, independente da dose, não influenciou na produtividade do algodão em caroço.

The objective of this study was to evaluate the efficiency of ammonium-glufosinate in management programs for weeds in cotton crop FiberMax 966 Liberty Link ® genotype. The experiment was installed in experimental area of Paiaguas Farm, located in municipality of Diamantino, Mato Grosso State. The experiment was conducted in a randomized block design with eight treatments and four replications. For weeds efficient management in FiberMax 966 LL genotype, the application of herbicide treatment in pre-emergence may reduce up to two post-emergence applications with no significant losses in production, but the pre-emergence treatment needs to be effective. If the application of a herbicide treatment in pre-emergence is not possible, the use of three sequential applications of ammonium-glufosinate (0.5, 0.4, 0.6 kg ha -1 ) at 10, 25 and 40 days after crop emergence (DAE) result in similar information. In the conditions that the experiment was conducted, all herbicide treatments were selective to the crop, without significant differences in bolls number and yield.

The objective of this study was to evaluate the efficacy in herbicides control applied in Crotalaria spectabilis and Crotalaria ochroleuca adult plants. Three experiments were installed with seven herbicides arranged in a randomized block design with four repetitions. It was realized visual evaluations of control at 3, 7, 14, 21, 35 and 42 after applications (DAA), and regrowth at 21, 28, 35 and 42 (DAA). It was concluded that treatment with sequential application of glyphosate(1,550 + 1,860 g ha -1 ) provided satisfactory control for both Crotalaria species. The treatments glyphosate + 2,4-D (1,240 + 806 g ha -1 ), glyphosate + flumioxazina (1,240 + 50 g ha -1 ) and glyphosate + metsulfuron-methyl (1,240 + 1.8 g ha -1 ), were efficient only for controlling C. spectabilis , while glyphosate + carfentrazone-ethyl (1,240 + 32 g ha -1 ) and glyphosate + saflufenacil (1,240 + 52.5 g ha -1 ) were efficient for controlling C. ochroleuca. Glyphosate + chlorimuron-methyl (1,240 + 10 g ha -1 ) treatmentwas not efficient for any species of sun hemp. Independent of flumioxazina doses (20; 30; 40; 50; and 60 g ha -1 ) it was not verified the effectiveness of control for C. spectabilis.

The objective of this work was to select appropriate bioindicators for monitoring the mobility in soil and persistence of amicarbazone, ametryne, diuron and clomazone herbicides. The experiments were conducted in greenhouse conditions, in polyethylene pots of 250 cm 3 with dystroferric Red Latosol. In each experiment, it was used one herbicide (amicarbazone, ametryn, diuron or clomazone) and three bioindicators (10 seeds of each specie), distributed in randomized blocks design in a factorial scheme 5 x 3, with three replications. Studied factors were herbicides rates (0; 12.5; 25; 50 and 100% of recommended rate of each herbicide) and species used as bioindicators ( Cucumis sativus, Brachiaria decumbens e Sorghum bicolor ). Thirty days after sowing, aerial parts of plants were cut and kept in a forced air oven at 40 °C in order to determine dry matter. Among bioindicators species tested, C. sativus was the one that had the highest sensitivity to the concentrations of amicarbazone and ametryne applied in soil. B. decumbens also had an appropriate response for biomonitoring clomazone and diuron, evidencing this idea for further experiments of mobility and persistence in clay soil. S. bicolor specie had the lowest inhibition of biomass among the bioindicators for all herbicides evaluated, therefore not indicated to evaluate the behavior of these herbicides in soil.

This study investigated the residual activity of different rates of the herbicides alachlor, oxyfluorfen, prometryne and S-metolachlor applied in pre-emergence in soils of contrasting textures. For that, eight simultaneous experiments were conducted with samples of PSAMENT (sandy texture) and RED LATOSOL (clay texture), which received alachlor (0; 2.40 and 3.36 kg ha -1 ), oxyfluorfen (0; 0.48 and 0.72 kg ha -1 ), prometryne (0; 0.75 and 1.50 kg ha -1 ) and S-metolachlor (0; 1.20 and 1.44 kg ha -1 ) applications. The treatments monitoring was made through sowing of bio-indicator ( Brachiaria decumbens or Cucumis sativus ). Control was assessed by scores from 0 to 100% at 0, 25, 50, 75, 100 days after application (DAA). Regardeless of rate, alachlor provided control around 80% to 66 DAA, in clay soil and up to 50 DAA in sandy. Oxyfluorfen showed control around 80% to 56 DAA to clay soil and up to 36 DAA to sandy, in both rates. Both rates of prometryne in clay soil provided control over 80% to 28 DAA, with residual activity higher in recommended rate (1.50 kg ha -1 ). In samples sandy, S-metolachlor provided the same control for both rates, controlling the bio-indicator at 80% up to 52 DAA, and for clay soil in rate at 1.44 kg ha -1 , presented 96% control the 80 DAA. Thereby, there was no increase in residual activity in sandy soil, even with the application of the recommended rate for clay soil.

The research aimed to evaluate the behavior of various pH reducers and metals complexers, under laboratory conditions. Were used 15 commercial products (10 pH reducers and 5 metals complexers), added to the spray mix. Five experiments were conducted; two to assess the stability of pH, after addition of pH reducers (Experiment 1) and metals complexers (Experiment 2) at 1% concentration, two to determine the necessary quantity of pH reducers (Experiment 3) and metals complexers (Experiment 4) to pH 3.5, an experiment to evaluate the reduction Ca activity in CaCO3, after addition of metals complexers (Experiment 5). Treatments with pH reducers do not differ and were statistically lower than the control (Experiment 1). Redumax was the complexer which has the lowest pH of the solution, with pH 1.3 (Experiment 2). In Experiment 3, pH Fos (0.06 L), P 30 (0.07 L) and Ubyphos (0.08 L) were the products that were used the smaller rate to reduce pH. The largest rate necessary was observed for NP10 with 0.8 L (Experiment 3). The product that uses the smallest volume in Experiment 4 was Redumax (0.12 L). L1 was the complexer that required higher rate, with 3.56 L (Experiment 4). No significant difference between L1 and control in Experiment 5, showing that this product does not confer complexant action.

The present work was aimed to evaluate the selectivity and efficiency of herbicides mixtures in sugar cane variety RB 83-5486. Four experiments were carried out in Nova Londrina (PR) and Marilena (PR). In each locality were developed two experiments. The experiments were conducted in randomized blocks, with nine treatments and four replications. In all experiments, the treatments were applied in pre-emergence: T1 (tebuthiuron) + (hexazinone + diuron), T2 (clomazone + ametrina) + (clomazone), T3 (clomazone + ametrina), T4 (trifloxysulfuron sodium + ametrina), T5 (trifloxysulfuron sodium + ametrina) + (hexazinone + diuron), T6 (clomazone + ametrina) + (hexazinone + diuron), T7 (hexazinone + diuron) + (clomazone), and two untreated checks (T8 - weedy and T9 – weed-free). Most treatments caused phytotoxicity in the culture. However, in all experiments, the crop recovered from the phytotoxicity caused by chemical treatments at 100 days after the application. T1 and T7 (Nova Londrina) and T5 and T6 (Marilena) provided total control of weeds up to 100 DAA. In both localities, the biomass accumulation at 150 DAA of the herbicides indicated no significant differences, in comparison with the weed-free ckeck. The weed interference reduced sugar cane biomass from 49,9% (Nova Londrina) to 56,2% (Marilena).

Two experiments were conducted to evaluate the influence from the addition of pH reducers and rates of glyphosate in the spray mix to Euphorbia heterophylla and Glycine max control. The treatments were arranged in a factorial scheme (4 x 2) + 1, randomized blocks design and four replications. Each experiment used a pH reducer (pH Fos ou Redumax), four rates of reducer (0, 50, 75 and 100% of the rate recommended), two rates of glyphosate (450 and 900 g ha-1) and an untreated check. The weed control was evaluated at 4, 6, 8, 10, 12 and 14 days after application (DAA) of treatments, in visual scale from 0 to 100% of control. In both experiments, 450 g ha-1 glyphosate, the addition of reducers in the spray mix provided greater weed control in relation to only glyphosate. There was no difference in 50, 75 and 100% of the rate recommended of reducers. With the use of adjuvant has a satisfactory control with half the recommended rate of glyphosate at 14 DAA. These results demonstrate the possibility of reduced rates of glyphosate when used these adjuvants in the spray mix.

O objetivo do trabalho foi avaliar a seletividade para a cultura da mandioca e o comportamento de varios herbicidas, aplicados em pre e pos-emergencia, no controle das plantas daninhas A ve na s ati v a, B i d e n s pilo sa, Com me l i n a b e n g h a l e n sis , R ap h a nu s sa t iv us e S i d a rh om bif o lia . O experimento foi conduzido em area de plantio direto, em Araruna, noroeste do Parana. Embora alguns herbicidas avaliados tenham se destacado em relacao ao controle de uma ou mais das especies de plantas daninhas e outros tenham demonstrado seletividade para a mandioca, os melhores resultados foram obtidos, considerando- se tanto a seletividade quanto a eficacia, com as misturas arnetryne+clornazone (1,50+1,00 kg/ha) e arnetryne+diuron (0,62+0,96 kg/ha), ambas aplicadas em pos-emergencia das plantas daninhas e quando a mandioca encontrava-se com 5 a 10% de brotacoes emergidas.