RESUMO:O controle químico eficiente da ferrugem asiática da soja depende da correta seleção da ponta de pulverização. Este trabalho teve o objetivo de avaliar o efeito da utilização de diferentes pontas de pulverização na aplicação de fungicida para o controle da ferrugem da soja. O ensaio foi conduzido no delineamento em blocos ao acaso, com quatro repetições, em esquema fatorial (4 x 2) + 1: quatro tipos de ponta de pulverização (jato plano defletor duplo, jato plano duplo com pré-orifício e jato cônico vazio com e sem indução de ar), dois volumes de aplicação (150 e 200 L ha -1 ) e um tratamento adicional que não recebeu fungicida. Realizou-se a semeadura direta da cultivar de soja M-SOY 8008 (ciclo precoce), avaliando-se, após a aplicação do fungicida tebuconazole, a deposição de calda no dossel da cultura, a severidade da ferrugem, o grau de desfolha e a produtividade. Concluiu-se que não houve influência dos tipos de pontas de pulverização e dos volumes de calda no controle da ferrugem. Na parte inferior do dossel, a cobertura proporcionada com a utilização das quatro pontas foi inferior a 7% da área, sendo, portanto, necessário buscar estratégias que incrementem essa deposição. O fungicida reduziu a severidade da ferrugem da soja, o que refletiu na produtividade, que foi, em média, 157% superior à obtida na testemunha. PALAVRAS-CHAVE: tecnologia de aplicação, Glycine max L., Phakopsora pachyrhizi. SPRAY NOZZLE EFFECT ON SOYBEAN RUST CHEMICAL CONTROLABSTRACT: Soybean rust chemical control depends on the correct selection of the spray nozzles. This study evaluated the spray nozzle effect on soybean rust control application. A randomized complete-block design with four replications was used, in a factorial model (4 x 2) + 1: four spray nozzles (hollow cone spray nozzles, with and without air induction, pre-orifice twin flat fan and turbo twin flat fan), two spray volumes (150 and 200 L ha -1 ) and the control (non-treated plot). M-SOY 8008 soybean (early cycle) was sown. After the application of the fungicide tebuconazole, with the different nozzles and volume rates, the spray deposition on the plant canopy, rust severity, defoliation level and yield were evaluated. The results showed that there was no influence of the nozzle type neither of the application volume in rust control. In the canopy lower part, the coverage obtained with the four nozzles was less than 7% of the area, therefore, it is necessary to find strategies to increase that deposition. The fungicide decreased rust severity, increasing soybean yield, which was, on average, 157% greater than that obtained in the control.

Arbuscular mycorrhizal fungi (AMF) species and/or phosphorus addition in the soil can affect secondary metabolism production and growth in plants. This study evaluated these effects on Piper divaricatum culture, which presents an essential oil rich in phenylpropanoids. Growth parameters, leaf volatile composition, total phenolic content, and the enzymatic activity of lipoxygenase (LOX) and phenylalanine ammonia-lyase (PAL) were monitored. At 90 days post inoculation (dpi), the treatments with AMF and AMF + P were more effective in terms of the number and biomass of leaves. In addition, the AMF group had increased plant height and root length. Phenylpropanoid and methyl eugenol contents were higher at 30 dpi in the P and AMF + P association treatments. However, at 90 dpi, the plants with P addition at 20 mg·dm−3 and AMF + 200 mg of P dm−3 showed higher phenolic contents and PAL activity, respectively. All treatments increased LOX activity, especially with P addition at 200 mg dm−3. These results demonstrate that P and AMF can be applied to optimize leaf biomass and volatile compound production in P. divaricatum.

Producing food in a sustainable manner, exploiting the genetic potential of crops and optimizing cultivation time to ensure increased production are the biggest challenges for agriculture. The cultivation of super-early common bean lineages with high productive capacity leads to minor water consumption in crops under irrigation and vacate the area in less time. The objective of this work was to evaluate the yield components of super-early cycle common bean cultivars, under irrigated system in function of sources of nitrogen (N) as well as to assess different application stages. The experiment was conducted in randomized block design in a factorial scheme 4x3 + 1, corresponding of four sources of N in coverage (urea, urea + ammonium sulfate, urea + ammonium sulfate + elemental sulfur and urea + elemental sulfur), three application stages (V3, V4 and R5) and a control treatment. The N incorporation did not influence on the grain yield of the super-early cycle common bean regardless of the source and season, whereas significant results were merely found when compared to the control. The number of pods was affected when the application was carried out at the R5 stage, with a significant reduction in this yield component. The relative chlorophyll index was lower when nitrogen coverage was performed at the R5 stage.