Abstract Several countries included the assessment of environmental drift contamination risk for the registration of pesticides. This practice is not yet totality effective in Brazil; however, due to the large number of pesticides in use, it is important to identify the real contamination risk during pesticide spraying. Therefore, this study determined the indices of environmental risks for exposure to drift from terrestrial applications of fungicides, herbicides, and insecticides that are used in soybean crops under Brazilian climate conditions and established buffer zones for the application of these products. Based on the three prediction drift models for soybeans in Brazil, risk indices were computed for aquatic organisms and terrestrial organisms according to the modelling procedures proposed by the POCER (Pesticide Occupation and Environmental Risk) and HAIR (Harmonized Environmental Indicators for Pesticide Risk) methodologies. In general, aquatic organisms are the most sensitive to drift contamination, being chlorothalonil, trifluralin and chlorpyrifos the ones that presented the higher risk indexes. No risk was found for earthworms; in contrast, the insecticides chlorpyrifos, spinosad and thiamethoxam presented risks to bees regardless of the nozzle (droplet size) used for the determination of the drift curve, resulting in the demand for different buffer zones.

O objetivo deste trabalho foi avaliar a deposição de calda pulverizada na cultura da batata e o espectro de gotas promovidos pela aplicação aérea e terrestre. O experimento foi repetido em duas épocas, em lavouras comerciais de batata, no delineamento inteiramente casualizado, em esquema fatorial 6 x 2, sendo seis formas de aplicação (aérea, a 15 e 30 L ha-1 com atomizador rotativo, e terrestre, a 200 e 400 L ha-1, com pontas de jato plano duplo, com indução de ar e jato cônico vazio); e duas composições de calda (água e água mais o adjuvante fosfatidilcoline + ácido propiônico). Avaliaram-se deposição de calda no dossel da cultura, perdas para o solo e deriva, pela técnica da adição de traçador para quantificação por espectrofotometria, e espectro de gotas, por meio da análise de papéis hidrossensíveis. A adição do adjuvante, de forma geral, proporcionou maior retenção de calda nas folhas inferiores e superiores. A diminuição do volume de aplicação proporcionou boa deposição de calda no alvo, sendo uma alternativa para aumento da capacidade operacional. A aplicação aérea mostrou-se tão eficiente quanto as aplicações terrestres na deposição de calda no alvo. A utilização do adjuvante não interferiu no diâmetro da mediana volumétrica e na percentagem do volume de gotas pulverizadas menores que 100 μm.

The aim of this study was to evaluate the sprayed liquid deposition in potato crop and the droplet spectrum, promoted by aerial and ground applications. The experiment was conducted in duplicate, in commercial potato crops, in completely randomized design, in a factorial model 6 x 2: six application methods (aerial, with rotative atomizer at 15 and 30 L ha-1, and ground, at 200 and 400 L ha-1 with air induction twin flat-fan and hollow-cone nozzles) and with two spray liquid compositions (water and water plus phosphatydilcoline + propionic acid adjuvant). It was evaluated spray liquid deposition in the crop canopy, run-off and drift, by addition of a tracer for quantification by spectrophotometry technique and the droplet spectrum by image analysis of water-sensitive papers. In general, the adjuvant addition provided a better spray liquid retention into lower and upper leaves. The decrease of spray volume provided a good spray liquid deposition on target that was contribute for an increase of the operational capacity. The aerial application was as efficient as the ground applications on the spray liquid deposition on the target. The use of adjuvant did not modify the volume median diameter and the percentage of spray volume in droplets smaller than 100 µm diameter.

O presente trabalho objetivou avaliar o espectro de gotas de pontas de pulverização hidráulicas, submetidas a diferentes pressões e composições de calda, por meio de um analisador de partículas a laser. Em delineamento inteiramente casualizado, avaliaram-se duas pontas de jato plano duplo com indução de ar (AD-IA/D 11002 e AD-IA/D 11004) e duas pontas de jato cônico vazio (MAG - 2 e MAG - 4), em esquema fatorial 3 x 2: três pressões de pulverização (207, 276 e 345 kPa para as pontas de jato plano duplo e 414; 483 e 552 kPa para as pontas de jato cônico); e duas composições de calda (água e água mais o adjuvante fosfatidilcoline + ácido propiônico). A adição do adjuvante reduziu o diâmetro da mediana volumétrica das gotas pulverizadas pelas pontas AD-IA/D 11002 e 11004; porém, teve efeito inverso com a ponta MAG - 4 e não o alterou com a ponta MAG - 2. Em condições climáticas adversas, não se recomenda o uso de pontas de jato cônico vazio, mesmo com a adição do adjuvante testado, em virtude do alto risco potencial de deriva.

The present study aimed to evaluate the droplet spectrum of hydraulic nozzles, under different pressures and spray liquid compositions, using a laser particle size analyzer. In a completely randomized design, two air induction twin flat-fan nozzles (AD-IA/D 11002 and AD-IA/D11004) and two hollow-cone nozzles (MAG - 2 and MAG - 4) were evaluated, in factorial design 3 x 2: tree spray pressures (207, 276 and 345 kPa for twin flat-fan nozzles, and 414, 483 and 552 kPa for cone nozzles); and two spray liquid compositions (water and water plus phosphatydilcoline + propionic acid adjuvant). The addition of adjuvant reduced the volume median diameter for the AD-IA/D 11002 and 11004 nozzles; however it had an opposite effect with the MAG - 4 nozzles and not changed with the MAG - 2 nozzles. In adverse weather conditions, it is not recommended the use of hollow cone spray nozzle, even with the addition of adjuvant tested because of the high risk potential of drift.