Allelopathy contributes to the sustainable management of weeds in growing areas, due to its ability to inhibit the development of weed species. This study aimed to evaluate the allelopathic effect of Pachyrhizus erosus extract on Euphorbia heterophylla and Bidens pilosa germination. The experiment was carried out in a completely randomized design, in a 2 x 2 x 4 factorial scheme, with four replications. The first factor corresponded to the plant portion (shoot and tuberous root), the second to the extract preparation method (water at room temperature and boiling) and the third to the extract concentrations (0 %, 25 %, 50 % and 100 %). Phytochemical analyses were performed to identify the presence of secondary metabolites. The variables germination percentage, germination rate index and dry biomass decreased with increasing aqueous extract concentrations for both E. heterophylla and B. pilosa. When applied a P. erosus crude shoot extract (boiling), decreases of 18 % and 92 % were observed in the E. heterophylla and B. pilosa germination, respectively, with a decrease of 91 % in the dry biomass of E. heterophylla seedlings. The tuberous root extract (boiling), on the other hand, reduced the germination percentages for E. heterophylla and B. pilosa in 18 % and 80 %, respectively. The phytochemical evaluation indicated the presence of flavonoids, coumarins and saponins in the shoot and tuberous root extracts, while tannins were only observed in the shoot extract. Thus, it can be concluded that P. erosus extracts display an allelopathic effect on the weed species evaluated.

Objetivou-se avaliar a tensão superficial e eficiência do espalhamento de gotas de soluções com herbicidas e adjuvantes em diferentes concentrações em folhas de Digitaria insularis. O delineamento experimental utilizado foi inteiramente casualizado, com quatro repetições. Os tratamentos utilizados foram glyphosate (Roundup Original®, 360 g L-1) na dose de 960 g L-1 e glufosinato-sal de amônio (Finale®, 200 g L-1), na dose de 400 g L-1 com adição dos adjuvantes: óleo mineral (Nimbus®), óleo vegetal (Aureo®) e glicerina (Hygrogem®, subproduto do biodiesel de soja), nas concentrações de: 0,00; 0,08; 0,16; 0,31; 0,63; 1,25; 2,50 e 5,00% (v/v), em folhas de Digitaria insularis. O espalhamento das gotas das soluções foram avaliadas nas faces foliares adaxial e abaxial. A eficiência no espalhamento de gotas nas folhas de D. insularis foi dependente do herbicida da face foliar, bem como da concentração dos adjuvantes avaliados. Observou-se que os adjuvantes foram eficientes em reduzir a tensão superficial das soluções com os herbicidas, com exceção para a glicerina adicionada ao glifosato. O glifosato+óleo mineral (3,2%) e o glufosinato+óleo vegetal (0,3%) foram os mais eficientes no espalhamento na face adaxial da folha de D. insularis, enquanto que o glifosato+óleo mineral (0,6%) e o glufosinato+óleo mineral (1,5%) foram os mais eficientes no espalhamento na face abaxial.

The intensive use of glyphosate can select resistant populations. This study aimed at evaluating the occurrence of glyphosate resistance in populations of D. insularis in agricultural areas. Three experiments were conducted in randomized block experimental design with four replications. The Resistance Degree (RD) was determined by a dose-response curve in the evaluated populations: Experiment 2012, São Camilo (R01 and R02) and Palotina (R03, R04 and S05-susceptible); Experiment 2013 Palotina (R06 and R12), Katueté/Paraguay (R07), Toledo (R08 and R10), Cascavel (R09), São Miguel do Iguaçu (R11), Dom Eliseu/Pará (S13-susceptible); Experiment 2015 Nova Aurora (R14), Iracema do Oeste (R15 and R16), Jesuitas (R17 and R18), Tupãssi (R19), Jotaesse (R20), Espigão Azul (R21) and Palmitopolis (S22- susceptible). In 2012, it was possible to confirm a moderate resistance (RD = 1.1 to 5.0) only in R03; and populations R01, R02 and R04 were highly resistant (RD>5.0). In 2013, populations R09, R10, R11 and R12 showed resistance, while R06, R07 and R08 were highly resistant. In 2015, the R14, R16, R18, R19 and R20 populations showed moderateresistance, and R15 and R18 were highly resistant. Only R21 was susceptible. It was found that 83% of producers use the no-tillage system, 100% use the succession soybean/corn with 90% transgenic varieties, 45% of producers cannot explain the procedure regulation/sprayer calibration. Around 62% use practices to prevent the selection of resistant biotypes. Resistance was confirmed in 89.5% of the populations. The adopted agronomic practices may explain these results.

The use of strategies such as sequential applications and mixtures may increase the control spectrum and the residual effect of chemical control of weed in the cassava crop. Thus, the objective was to evaluate the selectivity and efficacy of sequential applications and tank mixture of herbicides in the control of weed in the cassava crop cultivar 'Baianinha'. The experimental design was of randomized blocks, with eleven treatments and four replicates. The treatments consisted in: harrowed control, control without harrow, clomazone, mesotrione, S-metolachlor, clomazone+S-metolachlor, mesotrione+S-metolachlor, clomazone+mesotrione, sulfentrazone/clomazone, clomazone/[mesotrione+S-metolachlor], S-metolachlor/[mesotrione+clomazone]. The doses used for clomazone, mesotrione, sulfentrazone and S-metolachlor in the single applications, in sequence and in tank mixture were of 1.25, 0.24; 0.6 and 1.92 kg ha -1 , respectively. The first application of the sequential treatments occurred 50 days after planting (DAP) and the second at 92 DAP. The applications of mesotrione, mesotrione+clomazone and mesotrione+S-metolachlor, were carried late, at 92 DAP. Based on the data obtained, it is concluded that the mixture mesotrione+S-metolachlor and the sequential application of clomazone/ [mesotrione+S-metolachlor] were selective to cassava 'Baianinha' and efficient in the weed control (over 80% up to 148 days after planting).

-The objective of this study was to evaluate the chemical control of the species C. benghalensis and C. erecta with desiccants alone and mixtures, as well as the spreading of spray droplets on the leaf surfaces. The experimental design was completely randomized in a 2 x 16 factorial arrangement with four replications, totaling 32 treatments and 128 plots. The first factor is related to the species C. benghalensis and C. erecta and the second factor corresponds to the treatments carfentrazoneethyl in doses of 15, 30, 60 g ha -1

A new cycle of growth begins after pruning of cassava, and weed control is necessary. Thus, this study aimed to evaluate the selectivity and efficiency of sequential application of herbicides alone and in mixture with and without of foliar fertilizer after pruning of cassava. Two experiments were carried out in a randomized block design with four replications. The treatments of Experiment 1 consisted of control without weeding; control with weeding; mesotrione; mesotrione/mesotrione; mesotrione + foliar fertilizer/mesotrione + foliar fertilizer; mesotrione/mesotrione + foliar fertilizer; mesotrione + clethodim; mesotrione + clethodim + foliar fertilizer/mesotrione + clethodim + foliar fertilizer; mesotrione + clethodim/mesotrione + clethodim; mesotrione + clethodim/chlorimuron; mesotrione + clethodim/chlorimuron + foliar fertilizer; mesotrione + clethodim + foliar fertilizer/chlorimuron + clethodim + foliar fertilizer; mesotrione + clethodim/chlorimuron + clethodim]. Treatments of Experiment 2 consisted of control without weeding; control with weeding; chlorimuron; chlorimuron + foliar fertilizer/chlorimuron + foliar fertilizer; chlorimuron/chlorimuron; chlorimuron + clethodim; chlorimuron + clethodim + foliar fertilizer/chlorimuron + clethodim + foliar fertilizer; chlorimuron + clethodim/chlorimuron + clethodim; chlorimuron + clethodim/mesotrione + foliar fertilizer; chlorimuron + clethodim/mesotrione; chlorimuron + clethodim + foliar fertilizer/mesotrione + clethodim + foliar fertilizer; chlorimuron + clethodim/mesotrione + clethodim. The doses of mesotrione, clethodim, and chlorimuron used in both experiments were 240, 120, and 20 g ha-1, respectively, while 2.5 L of the commercial product Amino Plus® was used as foliar fertilizer. The first application was carried out at 50 days after pruning and the second application at 22 days after the first application. In Experiment 1, the application of mesotrione, mesotrione/mesotrione, and mesotrione + clethodim/mesotrione + clethodim showed selectivity to cassava and were efficient in weed control. In Experiment 2, chlorimuron + clethodim/mesotrione, chlorimuron + clethodim + foliar fertilizer/mesotrione + clethodim + foliar fertilizer, and chlorimuron + clethodim/mesotrione + clethodim were efficient in weed control, but no treatment was selective. The addition of foliar fertilizer to the spray solution did not contribute to increase selectivity.

Plantas de cobertura podem causar a supressão de plantas daninhas devido aos efeitos físicos e alelopáticos produzidos pela palhada. O objetivo deste trabalho foi o de avaliar o manejo da palhada de mucuna-preta (superficial ou incorporada) no controle de plantas daninhas na cultura da alface-crespa. O delineamento experimental foi o de blocos ao acaso, dispostos em parcelas subdividas, com quatro repetições. As parcelas compreenderam os dois sistemas de manejo de palhada da mucuna-preta (superficial ou incorporada) e as subparcelas foram constituídas pela prática da capina manual (com ou sem capina). Os resultados reportaram que não houve redução na massa seca de plantas daninhas com o uso da palhada superficial ou incorporada. No entanto, o manejo com a palhada proporcionou aumento de 27% na área foliar e de 20% na massa seca na cultura da alface-crespa, além de ganhos de 32% na produtividade, quando utilizada de maneira incorporada ao solo e associada à prática da capina. Desta forma, concluiu-se que apesar do pouco efeito na supressão das plantas daninhas, o uso de palhada de mucuna-preta pode proporcionar maior produtividade para a cultura da alface-crespa, especialmente quando incorporada ao solo.

The efficiency of fungal solutions, without wheat in organic systems, can be improved with the use of adjuvants. The objective of this study was to evaluate the dispersion of fungal droplets of organic fungicides with adjuvants in wheat leaves and disease control efficiency. The experimental design used was the completely randomized design in factorial scheme 2 × 3, with 6 repetitions. The first factor corresponded to fungal solutions bordeaux syrup (200 g L ) and second factor to the adjuvants: mineral oil and vegetable oil (0.5% v v -1 ) and one Witness without application.. On the adaxial side, the use of the mineral oil provided scatter of drop 111.8 and 25.7% higher, to the grouts without adjuvants and vegetable oil, respectively. The greater spreading of the droplets on the two foliar faces and a lower incidence of the diseases with the product of the lime sulfur syrup + mineral oil. The use of the adjuvants in the syrups evaluated with positive results in the production components, standing out the mineral oil.