RESUMO A deriva da pulverização de inseticidas pode proporcionar a redução da eficiência de controle e perda para o ambiente. Desta forma, foi conduzido um estudo com o objetivo de estudar o efeito de diferentes pontas de pulverização e adição de adjuvantes na calda inseticida, em relação ao espectro de gotas e deriva em túnel de vento. Os experimentos foram conduzidos no delineamento inteiramente casualizado, com quatro repetições, no esquema fatorial 5 × 3, constituído por cinco caldas, uma apenas com água e outras quatro com inseticida tiametoxam + lambda-cialotrina (sem adjuvante, Oro-solve, Wetcit Gold e Orobor N1), combinadas com três pontas de pulverização (AXI, JFC e J3D). Foi avaliado o espectro das gotas, através do diâmetro mediano volumétrico, amplitude relativa e porcentagem do volume de gotas com diâmetro ≤ 100 µm. A deriva foi avaliada em túnel de vento, a diferentes distâncias: 5, 10 e 15 m. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey. Além disso, foram realizadas análises de componentes principais. A aplicação do inseticida com os adjuvantes combinados com as diferentes pontas de pulverização alterou o espectro de gotas e o risco da deriva. A ponta AXI e a J3D associada aos adjuvantes Oro-solve e Wetcit Gold apresentaram maiores diâmetros medianos volumétricos das gotas e deriva a 5 m.

ABSTRACT Insecticide spray drift can lead to reduced control efficiency and loss of product to the environment. Thus, we conducted a study to evaluate the effect of different spray nozzles and the addition of adjuvants in insecticide spray on the resulting droplet spectrum and wind tunnel drift. All experiments were conducted in a completely randomized design with four repetitions using a 5 × 3 factorial scheme. Five spraying solutions were studied; one contained only water and the other four comprised thiamethoxam + lambda-cyhalothrin (no adjuvant, Oro-solve, Wetcit Gold, and Orobor N1), in combination with three spray nozzles (AXI, JFC, and J3D). The droplet spectrum was evaluated through the volumetric median diameter, relative amplitude, and percentage of the droplet volume with diameter ≤ 100 µm. The drifts were evaluated in a wind tunnel at 5, 10, and 15 m. Data were subjected to analysis of variance and means were compared using the Tukey’s test. In addition, a principal component analysis was performed. Application of the insecticide with the adjuvants combined with the different nozzles changed the droplet spectrum and the risk of drift. The AXI nozzle and the J3D associated with the Oro-solve and Wetcit Gold adjuvants resulted in a greater volumetric median diameter of the droplets and drifts were observed at 5 m.

Resumo: Objetivou-se avaliar a alelopatia de extratos aquosos de Digitaria insularis (capim-amargoso) sobre a germinação e crescimento inicial de culturas e plantas daninhas. Foram realizados três ensaios fatoriais (3x2x3), sendo o fator A as espécies vegetais: - culturas - Glycine max, Zea mays (milho), Phaseolus vulgaris (feijão), e plantas daninhas - Digitaria horizontalis, Echinochloa crusgalli and Bidens pilosa(picão-preto) -, o fator B origem do extrato de Digitaria insularis - raízes e parte aérea (folhas) - e fator C as concentrações de extrato - 0; 50 e 100%. Avaliou-se o percentual de germinação e o comprimento de parte aérea e de raiz das culturas e infestantes acima referidas. Entre as culturas, houve redução na germinação apenas na cultura do feijão (-12,5%) em resposta a 50%. do extrato aquoso radicular de Digitaria insularis O desenvolvimento inicial do milho e do feijão foram prejudicados. Sobre a soja não foram observados efeitos negativos. Entre as plantas daninhas, a espécie mais sensível foi o picão-preto, com reduções na germinação (-41%) e comprimento da parte aérea (-59%) e radicular (-84%) quando as sementes foram expostas a 100% do extrato da parte aérea de Digitaria insularis. As outras espécies de plantas daninhas também apresentaram redução em pelo menos uma das variáveis avaliadas. Em síntese, o efeito alelopático exercido pelo capim-amargoso pode estar relacionado com a sua grande competitividade com as culturas, assim como ao seu caráter dominante em áreas após a sua introdução.

Abstract: The objective of this study was to evaluate the allelopathy of aqueous Digitaria insularis (sourgrass) extracts on germination and initial growth of cultivated plants and weeds. Three factorial experiments (3x2x3) were carried out, being factor A - the tested plant species: crops - Glycine max (soybean), Zea mays (corn), Phaseolus vulgaris (bean), and weeds - Digitaria horizontalis, Echinochloa crusgalli and Bidens pilosa ; factor B - extracts of roots and shoots of sourgrass and factor C - concentration of the extract - 0, 50 and 100%. Germination percentage and the length of shoots and roots of the tested species were evaluated. Among the crops, there was a reduction in germination only in bean (-12.5%) in response to 50% of the aqueous root extract. The initial development of corn and beans were hampered. No negative effects were observed on soybean. Among the weeds, the most sensitive species was Bidens pilosa, with reductions in germination (-41%), length of shoots (-59%) and root (-84%) when the seeds were exposed to the 100% of the shoot extract of the sourgrass. The other weed species also suffered reductions in at least one of the evaluated variables. Therefore, the allelopathic effect exerted by sourgrass extracts may be related to its great competitiveness with crops, as well as to its dominant character in areas after its introduction.

RESUMO O controle de pragas, doenças e plantas daninhas nas culturas de larga escala dependem da aplicação de produtos fitossanitários. Estas aplicações estão sujeitas a diversos fatores que podem levar à deriva. O objetivo deste trabalho foi avaliar a deriva de pontas de pulverização de jato plano inclinado. A deriva foi coletada em túnel de vento de 10 m de comprimento, com sistema de pulverização no seu interior. As coletas foram efetuadas em cinco pontos na horizontal, de 2,0 a 6,0 m, da ponta de pulverização e cinco pontos na vertical, de 0,1 a 0,5 m da base inferior do túnel de vento, totalizando 25 pontos amostrais. A calda aplicada foi a mistura de glyphosate (sal de isopropilamina, 1.080 g e.a. ha-1) com 2,4-D (sal dimetilamina, 1.005 g e.a. ha-1). Foram utilizadas as pontas J3D 100 025, JGC 120 02, JAP 110 015 e ADI 110 015 (testemunha), com 37,5º, 20º, 15º e 0º de inclinação, respectivamente, em dois sentidos de pulverização: contra e a favor do sentido do fluxo de ar. As pontas J3D, JGC e JAP, quando inclinadas a favor do fluxo de vento reduziram a deriva em 16,1, 2,6 e 39,0%, respectivamente, em relação à testemunha, e quando inclinadas contra o fluxo, reduziram a deriva em 53,4, 3,9 e 18,6%, respectivamente. Pontas de pulverização de jato plano inclinado com indução a ar de segunda geração (JAP) e jato plano padrão inclinado (J3D), reduzem a deriva em relação à ponta sem inclinação, independente do sentido de fluxo de vento.

ABSTRACT Pest, disease and weed control in large-scale crops depend on the application of agrochemicals. These applications are subject to several factors that can lead to drift. The objective of this study was to evaluate the effect of spray nozzles with inclined flat jet, on the drift. The drift was collected in a 10 m wind tunnel, with a spray system inside. The samples were collected in 5 horizontal points, from 2.0 to 6.0 m away from the spray nozzle and 5 points in the vertical, from 0.1 to 0.5 m away from the lower base of the wind tunnel, totaling 25 sample points. The mixture applied was glyphosate (isopropylamine salt, 1080 g a.e. ha-1) with 2,4-D (dimethylamine salt, 1.005 g a.e. ha-1). The nozzles J3D 100 025, JGC 120 02, JAP 110 015 and ADI 110 015 (control), inclined by 37.5º, 20º, 15º and 0º, respectively, were used in two directions of spray: upwind and downwind of the air flow direction. The nozzles J3D, JGC and JAP, when inclined downwind reduced the drift by 16.1, 2.6 and 39.0%, respectively, relative to the control, and when inclined upwind, reduced drift by 53.4, 3.9 and 18.6%, respectively, relative to the control. Spray nozzles with second-generation air-induction inclined flat jet (JAP) and standard inclined flat jet (J3D) reduce the collected drift compared to the nozzle without inclination, regardless of wind flow direction.

ABSTRACT The method used for removal of brilliant blue dye may have an influence in interpreting the results of spraying deposition studies. The aim of this study was to assess the number of washings and water volumes for brilliant blue dye removal from soybean leaflets and glass slides in fungicide sprayings with and without adjuvants. A completely randomized experimental design was used in a 3 × 3 × 2 × 4 factorial scheme. The factors consisted of number of washings (1st, 2nd, and 3rd), water volume (15, 20, and 30 mL), target type (soybean leaflets and glass slides), and spray solutions (fungicide ProdutorBR® 0.5 L ha−1 without and with the adjuvants vegetable oil Agr’óleo® 0.5% v v−1, mineral oil Nimbus® 0.5% v v−1, and surfactant Silwet® 0.04% v v−1). Sprayings were carried out by using the nozzle model TT110015 at a pressure of 300 kPa (medium droplets). After spraying, targets were washed and the amount of brilliant blue dye removed per target area was detected by spectrophotometry. Brilliant blue dye removal is higher in glass slide when compared to soybean leaflets. With a single washing, a higher difficulty in removing the brilliant blue dye was observed for fungicide with vegetable oil. Only the first washing and a water volume of 15 mL are insufficient for brilliant blue dye removal from soybean leaflets and glass slides.