ABSTRACT Searching for novel sources of resistance to head blast is essential to strengthen wheat production in the Cerrado´s biome. The objective of this work was to evaluate disease intensity measures and yield for 2NS and non-2NS carriers wheat genotypes with varying heading times in Minas Gerais, Brazil. A total of fourteen wheat genotypes, two susceptible and twelve resistant to head blast, were sown in 2014, 2015, and 2017 at the Sertãozinho Experimental Station of Empresa de Pesquisa Agropecuária de Minas Gerais (Epamig) during three sowing dates without fungicide applications. The experimental design was a randomized complete block with three replicates. Blast incidence, severity, disease index and grain yield were influenced by the cycle of wheat genotypes and the sowing date, with the highest disease intensities and the lowest yields in the earliest sowing date. Blast incidence and disease index correlated negatively with grain yield and positively with percent yield losses. The group of wheat genotypes with higher grain yield (between 2,104.7 and 2,917.8 kg ha-1) and lower yield losses (between 44.3 and 54.8%) includes BR 18 as well as other five that do not carry the 2NS/2AS translocation: BRS Angico, PF 909, BRS 229, Embrapa 27, and CPAC 07340.

RESUMO: Este trabalho teve como objetivo avaliar as qualidades física e fisiológica, bem como a produtividade das sementes de milho, variedade UFVM 100 Nativo, produzidas em lavouras adubadas com diferentes níveis de resíduo avícola, em cobertura. O experimento foi instalado no delineamento em blocos casualizados, com seis tratamentos e quatro repetições, totalizando 24 parcelas. Os tratamentos consistiram da aplicação de 0,0; 1,5; 3,0; 4,5; 6,0 e 7,5 t/ha de resíduo avícola curtido. As sementes foram submetidas às seguintes avaliações: Teste de uniformidade, peso de mil sementes, germinação, vigor (primeira contagem de germinação, envelhecimento acelerado, teste de frio sem solo, porcentagem e velocidade de emergência em areia) e produtividade. Para avaliar o efeito das diferentes dosagens de resíduo avícola sobre as variáveis consideradas foram utilizados modelos de regressão linear. A qualidade das sementes não foi influenciada pelo efeito dos diferentes níveis de adubação. Dentre as dosagens utilizadas, recomenda-se a de 7,5 t/ha por proporcionar maior aumento da produtividade, o que poderá resultar em maior retorno financeiro ao produtor.

ABSTRACT: This study evaluated the physical and physiological qualities and productivity of corn seeds, a variety UFVM 100 Native, produced in plots fertilized in top dressing with different levels of poultry waste. The experiment was organized in a randomized block design, with six treatments and four repetitions, totaling 24 plots. The treatments consisted of the application of 0.0, 1.5, 3.0, 4.5, 6.0, and 7.5 t/ha of tanned poultry waste. The seeds were subjected to the following evaluations: uniformity test, thousand seed weight, germination, vigor (first germination count, accelerated aging, soilless cold test, percentage, and emergence rate in sand), and productivity. Linear regression models were used to evaluate the effects of different dosages of poultry waste on the variables considered. The quality of seeds was not influenced by the effects of different levels of fertilization. Among the dosages used, 7.5 t/ha is recommended because it provides a greater increase in productivity, which may result in a greater financial return to the producer.

ABSTRACT. Curves of crop growth and nutrient extraction and export are essential to develop fertilization strategies and management plans to maximize yield and reduce environmental impacts. Our study aimed to evaluate dry matter production and both extraction and export of macronutrients by arrowroots (Maranta arundinacea L.) to be used in further crop fertilization plans. To this purpose, two experiments were carried out in field conditions using the varieties Viçosa and Seta. The experimental design was randomized with four replications and nine periods of analysis, which were defined as days after planting (105, 135, 165, 195, 225, 255, 285, 315, and 345 DAP). Dry matter, extraction, and export of macronutrients by arrowroot seed-rhizomes, aerial parts, roots, and storage roots (rhizomes) were determined. The exports of N, P, K, Ca, Mg, and S of storage rhizomes of the variety Viçosa were 104.6, 51.83, 412.24, 15.85, 36.14, and 64.36 kg ha-1, while those of the seta variety were 160.6, 71.62, 521.31, 17.57, 60.09, and 160.41 kg ha-1, respectively. Both varieties proved to be efficient soil macronutrient extractors, mainly for K. The variety Seta had higher shoot, root, seed-rhizome dry matter contents, as well as greater macronutrient extractions and exports.

Abstract The ‘Ubá’ mango tree is found in all the cities of the Zona da Mata and its fruits are destined for both in natura consumption and for processing. However, there is a great heterogeneity among plants in the orchards, which contributes to low productivity. This study aimed to evaluate and select superior accessions of ‘Ubá’ mango trees collected in Ubá, Visconde do Rio Branco, and Viçosa, based on agronomic characteristics, aiming to produce high-quality fruits. The experiment was installed in Visconde do Rio Branco, MG. We evaluated 195 ‘Ubá’ mango tree accessions, in a completely randomized design, with four replications, of one tree each. The productions of the first five crops (mass and number of fruits, and alternate bearing index - per plant), and the fruit quality characteristics from the 2017-2018 crop (fruit, peel, seed and pulp masses; length, ventral and transversal diameters, peel and pulp color index, soluble solids content, titratable acidity, vitamin C and total carotenoids content of the pulp) were evaluated. Seventy-eight accessions of ‘Ubá’ mango trees were selected, 24 were based on accumulated production, over 200 kg of fruits per plant, and 59 accessions were based on fruit quality characteristics.

Resumo A mangueira ‘Ubá’ é encontrada em todos os municípios da Zona da Mata, e seus frutos são destinados tanto para consumo in natura como para o processamento. No entanto, há grande heterogeneidade entre plantas nos pomares, o que contribui para a baixa produtividade da cultura. O objetivo deste trabalho foi avaliar e selecionar acessos superiores de mangueiras ‘Ubá’ coletados em Ubá, Visconde do Rio Branco e Viçosa, com base em características agronômicas, visando à produção de frutos de qualidade. O experimento foi instalado em Visconde do Rio Branco-MG. Foram avaliados 195 acessos de mangueira ‘Ubá’, em delineamento inteiramente casualizado, com quatro repetições, de uma árvore cada. Foram avaliadas as produções das cinco primeiras safras (massa, número de frutos e índice de alternância de produção por planta) e as características de qualidade dos frutos, da safra 2017-2018 (massa do fruto, da casca, da semente e da polpa, comprimento, diâmetro ventral e transversal, índice de cor de casca e polpa, teor de sólidos solúveis, acidez titulável, vitamina C e teor de carotenoides totais da polpa). Foram pré-selecionados 78 acessos de mangueiras ‘Ubá’, sendo 24 com base em produção acumulada superior a 200 kg de frutos por planta e 59 acessos com base em características de qualidade dos frutos.

ABSTRACT Tephrosia egregia Sandwith is a species that develops in some States of the Northeast region of Brazil. It is propagated by seeds and has considerable potential for restoration. Thus, studies related to seed germination are important for the species. The aims were to characterize the post-seminal development and evaluate the germination response of the seeds under different temperatures and water stress and salt stress. Germination tests were performed at 20, 25, 30 and 20-30 °C and under PEG 6000 and NaCl concentrations (-0.2, -0.4, -0.6 and -0.8 MPa). The germination test should be conducted in a paper roll at 25 ºC for 14 days. Seed germination declines from the water potential of -0.2 MPa on; the species is sensitive to water stress. Under salt stress, there is more accentuated decline in germination as from -0.4 MPa, and this is an indication have a certain tolerance to salinity.

RESUMO Tephrosia egrégia Sandwith é uma espécie que se desenvolve em alguns Estados do Nordeste. Sua propagação é realizada por meio de sementes, sendo uma espécie potencial para restauração. Os objetivos foram caracterizar o desenvolvimento pós-seminal e avaliar a germinação das sementes sob diferentes temperaturas e sob estresse hídrico e salino. Testes de germinação foram conduzidos a 20, 25, 30 e 20-30 °C e sob concentrações de PEG6000 e NaCl (-0.2, -0.4, -0.6 e -0.8 MPa). O teste de germinação deve ser conduzido em rolo de papel sob temperatura constante de 25 ºC durante 14 dias. A germinação das sementes é reduzida a partir do potencial hídrico de -0.2 MPa, sendo a espécie sensível ao estresse hídrico. Sob estresse salino, a redução mais acentuada na germinação, a partir de -0.4 MPa, sendo isso um indicativo de uma certa tolerância à salinidade.

RESUMO: Objetivou-se com este estudo verificar a eficiência do 1,4-dimetilnaftaleno na supressão da brotação e a consequente manutenção da qualidade de tubérculos de batata das cultivares Asterix e Challenger, em diferentes temperaturas e tempos de armazenamento. Foram testados seis tratamentos, com e sem 1,4-DNM, nas temperaturas de 8 °C e 20 °C. As avaliações foram feitas aos 0, 45, 90, 135 e 180 dias após a aplicação. Os parâmetros avaliados foram: número de brotos, teores de açúcares solúveis totais, teores de açúcares redutores, e não redutores, e coloração dos palitos de batata após a fritura. Os efeitos do 1,4-DMN no controle da qualidade das batatas resultaram no controle da brotação e em menores teores de açúcares solúveis totais e de açúcares redutores, sobretudo na cultivar Challenger e à temperatura de 20 ºC.

ABSTRACT: The aim of this study was to verify the efficiency of 1,4-dimethylnapthalene in suppressing sprouting and the consequent maintenance of the quality of potato tubers of Asterix and Challenger cultivars, at different temperatures and storage regimes. Six treatments were tested, with and without 1.4-DNM, at temperatures of 8 ° C and 20 ° C. Assessments were made at 0, 45, 90, 135 and 180 days after application. The parameters evaluated were: number of sprouts, levels of total soluble sugars, levels of reducing and non-reducing sugars and coloration of potato strips after frying. The effects of 1.4-DMN on the quality control of potatoes resulted in sprout control and lower levels of total soluble sugars and reducing sugars, especially in the Challenger cultivar and at a temperature of 20 ºC.

Abstract This work aimed to analyze 1,4-DMN efficiency in the suppression of sprouting and the consequent maintenance of quality in potato tubers of Asterix and Challenger cultivars stored during different periods under varying temperatures: eight treatments with and without 1,4-DMN under temperatures of 8 °C and 20 °C. Treatments effect were evaluated after 0, 45, 90, 135 and 180 days after application. The evaluated parameters were the loss of fresh mass, length of the sprouts and activity of the enzymes polyphenoloxidase and peroxidase. The results indicate that the application of 1,4-DMN reduces the loss of fresh mass, this effect was more intense for the cultivar Challenger, at 8 °C. There were also significant effects in reducing the average length of the sprouts for both cultivars evaluated, after 180 days, at 20 °C. There was little or no difference in the level of oxidative stress caused in the tubers. Hence, the effects of 1,4-DMN on the quality control of potatoes included reduced loss of fresh mass and a shorter average length of sprouts for both cultivars evaluated compared to control, for both temperatures. These effects intensify in the cultivar Challenger and treatments with temperatures of 20 °C.

ABSTRACT The refrigerated induce the sweetening of the potato, which results in the dark color. The objective of this study was to determine the temperature and shelf life of Markies potato tubers under refrigerated storage for the processing of French fries. The levels of total soluble sugar (TSS), reducing sugars (RS), peroxidase (POD) and polyphenoloxidase (PPO) activity, color after frying and start of sprout were determined. The accumulation of TSS started at 30 days in the tubers at 4 and 5 °C and in the tubers at 6 and 8 °C, at 150 days. The activity of POD and PPO were not influenced by temperature or storage time. Tubers at 4 e 5 °C showed higher TSS and RS contents and darker color after frying than tubers stored at 6 and 8 °C which had their color maintained within the industry-acceptable standard up to 240 days of storage. Temperatures of 4 and 5 °C delayed the onset of sprouting, starting at 150 days, and at temperatures of 6 and 8 °C, the onset of sprouting occurred from 90 and 60 days of storage, respectively. It is concluded that the cultivar Markies should be stored at 6 °C for 240 days.

RESUMO O feijão-caupi está sujeito a perdas quantitativas e qualitativas durante o armazenamento devido ao ataque do inseto-praga Callosobruchus maculatus (Fabricius) (Coleoptera: Chrysomelidae). Para seu controle, é crescente o interesse por inseticidas proveniente das reações de metabólitos secundários produzidos por plantas, em decorrência de sua alta eficiência, ampla disponibilidade e seletividade para organismos alvos. Desta forma, o presente trabalho teve como objetivo avaliar a atividade fumigante do isotiocianato de alilo (AITC) no desenvolvimento de C. maculatus e seu efeito nas propriedades físicas do feijão-caupi. Para avaliação da taxa instantânea de crescimento populacional (ri) os insetos foram expostos às concentrações de AITC de 3,81, 5,71, 7,67, 9,41 e 17,85 mL m-3 de feijão-caupi, correspondentes às CL1, CL10, CL30, CL50 e CL95, durante 40 dias. Ao final deste período, as propriedades físicas do feijão-caupi foram analisadas. O grau de infestação aumentou consideravelmente com o decréscimo da concentração de AITC, assim como o teor de água e a condutividade elétrica. O percentual de germinação e a massa específica aparente diminuíram com a redução da concentração de AITC. A concentração subletal CL10 diminuiu a reprodução de C. maculatus e o grau de infestação dos grãos de feijão-caupi depois de 40 dias de armazenamento. O AITC inibe o desenvolvimento da espécie C. maculatus e contribui para a manutenção das propriedades físicas do feijão-caupi. Dessa forma, o AITC representa uma alternativa ao uso de inseticidas tradicionais além de apresentar potencial para o controle de insetos-praga de grãos armazenados.

ABSTRACT The cowpea is subject to both quantitative and qualitative loss during storage due to attack by the insect pest Callosobruchus maculatus (Fabricius) (Coleoptera: Chrysomelidae). There is a growing interest in controlling the pest using insecticides that result from the reactions of secondary metabolites produced by plants, due to their high efficiency, wide availability and selectivity for the target organisms. The present study aimed to evaluate the fumigant activity of allyl isothiocyanate (AITC) on the development of C. maculatus and its effect on the physical properties of the cowpea. To evaluate the instantaneous population growth rate (ri), the insects were exposed to concentrations of 3.81, 5.71, 7.67, 9.41 and 17.85 mL AITC m-3 cowpea (corresponding to LC1, LC10, LC30, LC50 and LC95) for 40 days, after which the physical properties of the cowpea were analyzed. The degree of infestation increased considerably with the reduction in AITC concentration, as did the water content and electrical conductivity. The germination percentage and apparent density decreased with the reduction in AITC concentration. The LC10 sublethal concentration reduced reproduction in C. maculatus and the degree of infestation of the cowpea after 40 days of storage. AITC inhibits the development of C. maculatus and helps maintain the physical properties of the cowpea, thereby representing an alternative to the use of traditional insecticides and showing potential for the control of insect pests in stored grain.

ABSTRACT The purpose of this study was to assess the effect of different herbicide treatments on moisture removal and calorific power of biomass sorghum for co-generation of electric energy through burning. The experiment was conducted in randomized complete block design with four replicates per treatment and a 6x4 factorial scheme (six herbicide treatments x four intervals between spraying and harvesting). The herbicide treatments were: two different doses of glyphosate (1.92 kg a.i. ha-1 and 3.84 Kg a.i. ha-1), paraquat (0.4 Kg a.i. ha-1), a commercial mixture of paraquat + diuron (0.6 + 0.3 Kg a.i. ha-1), glufosinate-ammonium (0.8 Kg a.i. ha-1) and control (unsprayed). The intervals between spraying and harvesting assessed were 7, 14, 21 and 28 days after desiccation (DAD). It was assessed: the number of leaves per plant, moisture content of leaves, panicles, culm and whole ground plants and Superior Calorific Power (SCP). The herbicides paraquat and paraquat + diuron promotes defoliation, after 14 DAD. Glyphosate, paraquat, paraquat + diuron and glufosinate-ammonium reduce leaf and panicle moisture, despite only glyphosate reduces moisture in the culm. The herbicides do not affect the SCP of biomass sorghum. Therefore, the herbicides, especially glyphosate, have high potential for pre-harvest desiccation in biomass sorghum.

Resumo Avaliou-se a composição bromatológica de silagens de soja sem aditivos (controle), com inoculante microbiano (I), com I + melaço (I+M) e com melaço (M). As plantas de soja foram colhidas no estádio R6 de desenvolvimento e ensiladas em silos laboratoriais de PVC, com capacidade de 2 kg. O inoculante utilizado foi o SIL ALL C4 da Alltech do Brasil associado ou não com 2,5% de melaço, na base da matéria seca. Utilizou-se um esquema fatorial 4 × 6 (4 aditivos × 6 períodos de fermentação) em um delineamento completamente casualizado com 3 repetições. Os períodos de fermentação avaliados foram: 1, 3, 7, 14, 28, e 56 dias. Excluindo os teores de matéria seca e de proteína bruta foi observado efeito (P<0,05) da interação aditivos e período de fermentação sobre as silagens. Observou-se maiores valores médios de matéria seca, de 290,02 g kg-1, e de proteína bruta, de 151,28 g kg-1, para as silagens I+M e M, respectivamente. Foi observado menores valores (P<0,05) de NIDN e de NIDA nas silagens I+M, de 180,47 and 125,07 g kg-1, respectivamente. A adição de inoculante associada ou não ao melaço altera a composição bromatológica de silagens de soja.

Abstract Chemical composition was assessed in soybean silages without any additive (control), with a microbial inoculant (I), with I + molasses (I+M), and with molasses only (M). Soybean plants were harvested at the reproductive 6 (R6) stage and ensiled in 2 kg-capacity PVC laboratory silos. The SIL ALL C4 inoculant produced by Alltech Brazil was used in combination with or without 2.5% molasses added to the natural matter base. A 4 × 6 factorial arrangement (4 additives × 6 fermentation periods) in a completely randomised design with 3 replications was used. The assessed fermentation periods were 1, 3, 7, 14, 28, and 56 days. Excluding the dry matter and crude protein contents it was observed an interaction effect (P<0.05) between the additive and fermentation periods in the silages. It was observed higher average values of dry matter, equal 290.02 g kg-1, and crude protein, equal 151.28 g kg-1, to I+M and M silages, respectively. It was observed lowest values (P<0.05) to neutral detergent insoluble nitrogen (NDIN) and acid detergent insoluble nitrogen (ADIN) contents in I+M silages, equal 180.47 and 125.07 g kg-1, respectively. The addition of inoculant associated or not with molasses improved affect the chemical composition of soybean silages.

Abstract Studies evaluating the influence of nutrients on plant anatomy are very important because nutritional deficiencies can alter the thickness and shape of certain tissues, compromising their functionality what can explain the reduction of productivity. The aim of this study was to characterize the anatomical changes in cherry tomato plants subjected to calcium (Ca) and magnesium (Mg) deficiencies. The experiment was conducted in nutrient solution and the plants subjected to three treatments: complete solution (Control), Ca restriction (1 mmol L-1 of Ca) and Mg omission (without Mg). The experimental design was completely randomized, with three repetitions. Sixty days after seedling transplanting leaves and stem were collected and submitted to anatomical evaluations. Ca or Mg deficiency promotes most evident anatomical changes in chlorophyllous and vascular tissues of the leaves, rather than in the stems. Leaves of ‘Sindy’ tomato plants with a concentration of 1.7 g kg-1 of Mg and visual symptoms of Mg deficiency present hyperplasia of both tissues, phloem and xylem. This deficiency also promotes increases in the thickness of mesophyll, spongy parenchyma and palisade parenchyma, and consequently of leaf thickness. The midrib of the leaves with a concentration of 10 g kg-1 of Ca, without visual symptoms of deficiency presented phloem hypertrophy and hyperplasia.

RESUMO: Este trabalho teve como objetivo ajustar modelos de regressão quantílica não linear para o estudo do acúmulo de matéria seca total em plantas de alho ao longo do tempo, e compará-los com modelos ajustados pelo método dos mínimos quadrados. A matéria seca total de nove acessos de alho pertencentes ao Banco de Germoplasma de Hortaliças da Universidade Federal de Viçosa (BGH/UFV) foi avaliada em quatro períodos (60, 90, 120 e 150 dias após plantio), e estes valores foram utilizados para o ajuste de modelos de regressão - não linear - logística. Para cada acesso, foram ajustados um modelo de regressão quantílica (τ=0,5) e um modelo pela metodologia dos mínimos quadrados. Para avaliar a qualidade de ajuste dos modelos foi utilizado o Critério de Informação de Akaike. Os acessos foram agrupados pelo algoritmo UPGMA, utilizando as estimativas dos parâmetros com interpretação biológica como variáveis. A regressão quantílica não linear foi eficiente no ajuste de modelos para descrição do acúmulo de matéria seca ao longo do tempo. As estimativas de parâmetros foram mais uniformes e robustas na presença de dados assimétricos, variâncias heterogêneas e de valores discrepantes.

ABSTRACT: The objective of this study was to adjust nonlinear quantile regression models for the study of dry matter accumulation in garlic plants over time, and to compare them to models fitted by the ordinary least squares method. The total dry matter of nine garlic accessions belonging to the Vegetable Germplasm Bank of Universidade Federal de Viçosa (BGH/UFV) was measured in four stages (60, 90, 120 and 150 days after planting), and those values were used for the nonlinear regression models fitting. For each accession, there was an adjustment of one model of quantile regression (τ=0.5) and one based on the least squares method. The nonlinear regression model fitted was the Logistic. The Akaike Information Criterion was used to evaluate the goodness of fit of the models. Accessions were grouped using the UPGMA algorithm, with the estimates of the parameters with biological interpretation as variables. The nonlinear quantile regression is efficient for the adjustment of models for dry matter accumulation in garlic plants over time. The estimated parameters are more uniform and robust in the presence of asymmetry in the distribution of the data, heterogeneous variances, and outliers.

Com o objetivo de avaliar o efeito de diferentes ambientes sobre a qualidade fisiológica e atividade enzimática de sementes de milho, dois lotes de sementes da cv. ‘BR 106’ foram armazenados em embalagem de papel em três ambientes: câmara fria (12±2°C/60±5%UR), ambiente não controlado (média de 21,6°C/71%UR) e câmara controlada (30±2°C/70±5%UR). A qualidade fisiológica (germinação e vigor) e as atividades da peroxidase, catalase e α-amilase foram avaliadas no inicio e a cada 90 dias de armazenamento. A qualidade fisiológica das sementes foi reduzida ao longo do período de armazenamento, independente dos lotes, com menores reduções nas armazenadas em temperaturas mais baixas. A atividade enzimática da peroxidase, catalase e α-amilase decrescem com o aumento do período e da temperatura de armazenamento das sementes, sendo eficiente na avaliação da qualidade fisiológica de sementes armazenadas.

With the objective of evaluating the effect of different environments on the physiological quality and enzyme activity of maize seed, two seed lots of cv. ‘BR 106’ were stored in paper packing in three environments: cold chamber (12±2°C/60±5%UR), uncontrolled (mean 21.6°C/71%UR) and controlled chamber (30±2°C/70±5%UR). The physiological quality (germination and vigor) and the activities of peroxidase, catalase, and α-amylase were evaluated at the beginning and every 90 days of storage. The seed quality was reduced throughout the storage period, regardless of the lots, with smaller reductions when stored in low temperature. The enzymatic activity of peroxidase, catalase and α-amylase decreases with increasing time and temperature of storage of seeds, being efficient in assessing the physiological quality of stored seeds.

RESUMO O tomateiro é uma das principais culturas no Brasil. No seu cultivo em larga escala, são aplicados agrotóxicos sobre a planta para impedir a ação direta ou indireta de formas de vida animal ou vegetal, visando uma maior produtividade e qualidade do fruto. Os produtos utilizados podem, no entanto, afetar a saúde dos trabalhadores envolvidos na atividade caso sejam usados incorretamente. Sendo assim, foi desenvolvido um protótipo de pulverizador autopropelido controlado e monitorado à distância, via sinais de rádio, para ser utilizado em lavouras de tomate, minimizando com isso o contato dos trabalhadores com as substâncias químicas utilizadas na tarefa de pulverização. Esse protótipo é formado basicamente por um mini-trator agrícola, por um pulverizador pneumático motorizado (atomizador) e por um conjunto de sensores e atuadores eletrônicos e mecânicos, que permitem o comando remoto do conjunto e a visualização das imagens captadas por uma câmera de vídeo em um tablet. Após o desenvolvimento, as principais caraterísticas dimensionais, ponderais e operacionais do protótipo foram levantadas e ele também foi utilizado para pulverizar dez plantas numa lavoura de tomate, sendo observados sete pontos distintos em cada uma delas. Os resultados foram analisados estatisticamente, obtendo-se os seguintes coeficientes de variação: 15,13% na cobertura da pulverização, 18,70% na densidade de gotas e 16,68% na deposição de produto nos folíolos. Com base nesses valores, concluiu-se pela viabilidade do desenvolvimento de um protótipo de pulverizador autopropelido controlado e monitorado remotamente e a sua utilização na pulverização de lavouras de tomate.

ABSTRACT The tomato is one of the main crops in Brazil. In large-scale cultivation, pesticides are applied to the plant to prevent the direct or indirect action of animal or vegetable life, aiming at higher productivity and better quality fruit. However, the products, if used incorrectly, may affect the health of workers involved in the activity. A prototype of a self-propelled sprayer, remotely controlled and monitored via radio signals, was therefore developed to be used in tomato crops, thus minimising worker contact with the chemical substances used when spraying. The basic prototype comprises an agricultural mini-tractor, a motorised pneumatic sprayer (atomiser) and a set of electronic and mechanical sensors and actuators, which allow the assembly to be controlled remotely and images captured by a video camera to be viewed on a tablet. After development, the principal dimension, weight and operational characteristics of the prototype were identified; the prototype was also used for spraying ten tomato plants in the crop, with seven different points being observed for each plant. The results were analysed statistically, giving the following coefficients of variation: 15.13% for spray coverage, 18.70% for droplet density and 16.68% for product deposition on the folioles. Based on these values, it was concluded that the development of a remotely controlled and monitored self-propelled sprayer prototype, and its use in spraying tomato crops, were viable.