R E S U M OÉ crescente a preocupação com os riscos da deriva em pulverizações com produtos fitossanitários e seus efeitos sobre o ambiente, sendo cada vez mais importante a utilização de tecnologias que forneçam maior segurança. Objetivou-se avaliar pontas de pulverização de jato plano inclinado e jato plano com indução de ar empregadas na pulverização com diferentes adjuvantes de uso agrícola na estimativa do risco potencial de deriva por meio dos depósitos e espectro das gotas. Os tratamentos consistiram de quatro soluções combinadas a duas pontas de pulverização. Os depósitos foram medidos em diferentes distâncias e alturas, em túnel de vento. Os indicadores relativos ao espectro de gotas foram: porcentagem do volume de gotas com diâmetro menor ou igual a 100 μm, diâmetro da mediana volumétrica (DMV) e a amplitude relativa, determinados em um medidor de partículas a laser. A adição do adjuvante polímero vegetal à água propiciou diminuição dos depósitos, redução da porcentagem do volume de gotas com diâmetro menor ou igual a 100 μm e DMV maiores, indicando redução do risco potencial de deriva. Depósitos maiores foram obtidos com a ponta de jato plano inclinado sem adição de adjuvantes à calda, representando maior risco potencial de deriva em pulverização.Interaction spray nozzle-adjuvant to estimate potential risk of spray drift A B S T R A C TThere is increasing concern about the risk of pesticide spray drift and their effects on the environment, becoming increasingly important to use spray technologies that provide greater security. This study aimed to evaluate flat angled fan nozzle and the air induction flat fan nozzle combined to different spray adjuvant for agricultural use to estimate the potential risk of spray drift through deposits and spectrum of drops. The treatments were four spray solutions combined with two spray nozzles. Spray deposits were measured at different distances and heights into a wind tunnel. Indicators of droplet spectrum were: percentage of droplets volume smaller than or equal to 100 µm of diameter, volume median diameter (VMD), and relative span factor, obtained in a laser particle analyser. The addition of vegetal polymer adjuvant to water resulted in lower levels of spray deposits, reducing the percentage of droplets volume smaller than or equal to 100 µm of diameter and showed larger VMD, indicating low potential risk of spray drift. Higher deposit levels were obtained under angled flat fan nozzle without addition of adjuvant to the spray solution, which represents a greater potential risk of spray drift. Palavras

Tractor traveling speed can influence the quality of spraying depending on the application technology used. This study aimed to evaluate the droplet spectrum, the deposition and uniformity of spray distribution with different spraying systems and traveling speeds of a selfpropelled sprayer in two phenological stages of the cotton plant (B9 and F13). The experimental design was randomized blocks and treatments were three spraying techniques: common flat spray tips; tilted flat jet with air induction, at 120 L ha -1 ; and rotary atomizer disk, 20 L ha -1 , combined with four traveling speeds: 12, 15, 18 and 25 km h -1 , with four replications. Spraying deposition was evaluated for both leaf surfaces from the cotton plant apex and base (stage B9) and middle part of the plant (stage F13) with a cupric marker. A laser particle analyzer also assessed the droplet spectrum. The centrifugal power spray system produces more homogeneous droplet spectrum and increased penetration of droplets into the canopy in both phenological stages. Variation on the operating conditions necessary for increased traveling speed negatively influences the pattern of spraying deposits.KEYWORDS: application technology, rotary atomizer disk, rotating nozzle, Gossypium hirsutum L. SISTEMAS DE PULVERIZAÇÃO E VELOCIDADE DE DESLOCAMENTO NO DEPÓSITO E ESPECTRO DE GOTAS EM ALGODOEIRORESUMO: A velocidade de deslocamento pode influenciar na qualidade da pulverização em função da tecnologia de aplicação utilizada. O trabalho teve como objetivo avaliar o espectro de gotas, a deposição e a uniformidade de distribuição da pulverização com diferentes sistemas de pulverização, e a velocidades de deslocamento de um pulverizador autopropelido, em dois estádios fenológicos do algodoeiro (B9 e F13). O delineamento experimental foi o de blocos ao acaso, e os tratamentos foram três técnicas de pulverização: pontas de jato plano comum; jato plano inclinado com indução de ar, a 120 L ha -1 ; e atomizador rotativo de disco, a 20 L ha -1 , combinados a quatro velocidades de deslocamento: 12; 15; 18 e 25 km h -1 , em quatro repetições. A deposição da pulverização foi avaliada em ambas as superfícies foliares do ápice e da base do algodoeiro (estádio B9) e a parte média da planta (estádio F13), com um marcador cúprico. Também foi avaliado o espectro de gotas por um analisador de partículas a laser. O sistema de pulverização de energia centrífuga produz espectro de gotas mais homogêneo e maior penetração das gotas no dossel, em ambos os estádios fenológicos. A variação nas condições operacionais necessárias para o aumento da velocidade de deslocamento influencia negativamente sobre o padrão dos depósitos da pulverização. PALAVRAS-CHAVE:Tecnologia de aplicação, atomizador rotativo de disco, bico rotativo, Gossypium hirsutum L.Spraying systems and traveling speed in the deposit and spectrum of droplets in cotton plantEng.

Seletividade do nicosulfuron em três estádios fenológicos ... 1Recebido para publicação em 15.6.2011 e aprovado em 16.12.2011. ) e três estádios fenológicos (V3, V5 e V7), totalizando 15 tratamentos. A resposta do milho-pipoca ao nicosulfuron foi verificada por meio de avaliações visuais de intoxicação e efeitos sobre a altura das plantas aos 7, 14 e 28 dias após a aplicação, componentes de produção (plantas m -2 , espigas m -2, comprimento de espigas, massa de 100 grãos e número de grãos por espiga) e produtividade de grãos. De modo geral, o híbrido A 448 White evidenciou maior nível de tolerância aos tratamentos aplicados no estádio V3. A produtividade de grãos não sofreu interferência significativa do nicosulfuron nos estádios V3 e V5, mesmo na dosagem mais alta. Assim, dentro do intervalo de dosagens avaliado, o herbicida nicosulfuron pode ser aplicado em plantas de milho-pipoca nos estádios V3 e V5, sem riscos de redução de produtividade.Palavras-chave: Zea mays, herbicida, sulfonilureias, tolerância.ABSTRACT -This work aimed to evaluate the selectivity of the herbicide nicosulfuron toward popcorn (hybrid A 448 White), applied at three growth stages. The experiment was arranged in a randomized complete block design, with four replications. The treatments were organized as a factorial combination, including five nicosulfuron doses (0; 17.5, 35, 70, and 140 g ha -1 ), and three growth stages (V3, V5, and V7), totaling fifteen treatments. The response of the hybrid to nicosulfuron was evaluated in terms of visual injury ratings and effects on plant height at 7, 14, and 28 days after application, yield components (plants m -2 , cob m -2 , cob length, 100 grains weight and kernels/cob), and final yield. In general, hybrid A 448 White showed a higher level of tolerance to the treatments applied at the V3 stage. Grain yield did not suffer significant interference of nicosulfuron at the V3 and V5 growth stages, even at the highest dose. Thus, at the dose range evaluated, nicosulfuron can be used safely at the V3 and V5 growth stages, without risk of reduced yield.

The addition of commercial formulations and adjuvants to a tank mix may result in differences in the wettability on the plant surface, foliar uptake and herbicide efficacy. Thus, the objectives of this study were to evaluate the influence of glyphosate formulations and tank-mixture adjuvants on the contact angle (CA), uptake, metabolism and sourgrass control and the damage to the cuticular microstructure of this species caused by herbicide solutions. For this purpose, assays were carried out in a completely randomized design, and treatments distributed in a 2x5+1 factorial scheme with five replications. Two glyphosate formulations isopropylamine salt (SL) and ammonium salt (WG) combined or not with the adjuvant methylated soybean oil (MSO), mineral oil (MO), ethoxylated alkyl ester (EAE) or polyoxyethylenealkylphenol ether (PAE); and one control (water) were evaluated. CA measurements of the droplets deposited on a sourgrass leaf surface and on the standard surface (parafilm) were obtained using a tensiometer. Herbicide uptake and shikimate accumulation were simultaneously determined by chromatography and spectrometry. The control effect was assessed by observing plant survival dry weight reductions. The glyphosate SL and WG formulations had similar effects on the variables analyzed. However, mixing the adjuvants EAE, MO or MSO with either formulation of herbicide led to greater wettability and more severe damage to the cuticular microstructure, favoring glyphosate uptake and shikimate accumulation. Despite evidence regarding the treatments containing oils/surfactants, the control effect on sourgrass was similar. The combination of glyphosate formulations with such adjuvants is potentially more effective and guarantees satisfactory sourgrass control.

PULVERIZAÇÃO EM TAXA VARIADA NA CULTURA DO ALGODÃO1   ANDRÉ JÚNIO ANDRADE PERES1, CARLOS GILBERTO RAETANO2, FÁBIO HENRIQUE ROJO BAIO3, DANILO CARVALHO NEVES4, JHONATAN DIEGO CAVALIERI5   1Departamento de Fitossanidade – Faculdade de Agronomia, UFG, Avenida Esperança, s/n, Cep. 74690-900, Goiânia, GO, Brasil, e-mail: andrejaperes@yahoo.com. 2Departamento de Proteção Vegetal – Faculdade de Ciências Agronômicas, Unesp, Avenida Universitária, 3.780, Cep. 18610-034, Botucatu, SP, Brasil, e-mail: carlos.raetano@unesp.br. 3CPCS – UFMS, Rodovia MS 306, Km 105, Cep. 79560-000, Chapadão do Sul, MS, Brasil, e-mail: fabiobaio@ufms.br. 4CPCS – UFMS, Rodovia MS 306, Km 105, Cep. 79560-000, Chapadão do Sul, MS, Brasil, e-mail: danilocna@gmail.com. 5Departamento de Proteção Vegetal – Faculdade de Ciências Agronômicas, Unesp, Avenida Universitária, 3.780, Cep. 18610-034, Botucatu, SP, Brasil, e-mail:jdcavalieri@gmail.com.   RESUMO: O monitoramento do algodoeiro é realizado para identificar zonas de manejo para aplicação localizada de agroquímicos. A variação do volume de aplicação está entre as técnicas que determinam a qualidade das pulverizações. A inconstância da velocidade de deslocamento do pulverizador é um ponto agravante para a boa qualidade da operação. A presente pesquisa objetivou avaliar o espectro de gotas da pulverização e deposição da calda nas folhas, simulando uma aplicação à taxa variada, com variação do volume. Os tratamentos consistiram na pulverização dos volumes de 100 e 130 L.ha-1. Foram analisados: diâmetro das gotas, amplitude relativa e depósito da pulverização em folha do terço superior do algodoeiro. Os pontos amostrais foram marcados com auxílio de GPS. A velocidade de deslocamento foi registrada pelo controlador eletrônico, obtendo as pressões de trabalho nas respectivas velocidades. O espectro de gotas foi determinado pelo analisador de gotas a laser e a deposição por espectrometria de fluorescência. Em taxa variada a uniformidade do espectro de gotas é inversamente proporcional à elevação da velocidade, pressão e volume de calda. Obteve incrementos de depósitos com volume de 130 L.ha-1. Aplicação localizada de agroquímicos, utilizando variação do volume de aplicação, recomenda-se adotar maiores volumes de calda.   Palavras-chave: Gossypium hirsutum, tecnologia de aplicação, pulverização em taxa variada.   VARIABLE RATE OF SPRAYING IN COTTON CROP   ABSTRACT: Cotton crop monitoring is carried out to the identification of management zones for localized agrochemicals application. The application volume variation is the techniques that determine the spray quality. However, the inconstancy of spraying travel speed in field situations is an aggravating point for operation quality improvement. Thus, the present research aimed to evaluate the spray spectrum droplets and liquid deposition on leaves, simulating a variable rates application with volume variation. The treatments consisted in spraying volumes of 100 and 130 L.ha-1. The replicates varied according to the analyzed variables: diameter of the droplets with 10, 50 and 90% of accumulated volume, relative amplitude and liquid deposit on the leaves from upper third. The samples points were marked using GPS. An electronic spray controller machine recorded the spraying speed of displacement, at each point, obtaining the working pressures at the respective speeds. The laser drop analyzer determined the droplet spectrum and the spray deposition were analyzed by fluorescence spectrometry. In spraying at varied rates, the droplet spectrum uniformity is inversely proportional to the speed increase, pressure and syrup volume. It obtained increment deposit when the volume of application reached 130 L.ha-1. In a localized application of agrochemicals using the application volume variation technique it is recommended to adopt larger liquid volumes.   Keywords: Gossypium hirsutum, application technology, spraying at varied rates.

The intensive use of glyphosate in agricultural areas has increased the frequency of weeds that are resistant to herbicides. Thus, this study was aimed to assess the sensitivity and resistance level of Digitaria insularis (L.) Fedde (sourgrass) populations to glyphosate. Sixtytwo sourgrass populations were collected from the states of Paraná and São Paulo, Brazil, and subjected to glyphosate application at 1,080 and 2,160 g of acid equivalent (a.e.) • ha -1 in screening assays. Five sourgrass populations were selected, three of which are resistant and two of which are susceptible to glyphosate, to determine the resistance factors (RFs) through dose-response studies at two phenological stages of plant growth: the 2-4-leaf stages and the 2-4-tiller stage. The trials were conducted in a greenhouse in accordance with a completely randomized design. In both trials, the control was evaluated based on the score of the visual control symptoms (VC) and the percentage of dry matter (DM) in relation to those of the control (without application). In the screening test, the data obtained for the response variables were adjusted for frequency curves by following the regression model proposed by Gompertz. The results indicated low sensitivity of D. insularis to glyphosate in 100% of the samples from areas in which soybeans are tolerant to this herbicide. Populations with susceptible plants were found in fallow areas, pasture areas and sugar cane fields. Based on the values of VC 50 and DM 50 , the maximum RF obtained among the populations was 15. More advanced stages of development make sourgrass control difficult, requiring doses that are 3.5 times greater than those at the initial stage.