Parâmetros técnicos da tecnologia de aplicação usados na pulverização hidropneumática em diferentes condições operacionais Technical parameters of the application technology applied to hydropneumatic spraying in different operating conditions RESUMO: O Brasil é o maior produtor e exportador mundial de café e vem enfrentando dificuldades em razão da suscetibilidade da cultura à ocorrência de insetos. Objetivou-se, com este trabalho, avaliar parâmetros da aplicação utilizando a pulverização hidropneumática com o uso de diferentes volumes de calda e pontas de pulverização, na presença e ausência de adjuvante agrícola. O trabalho foi conduzido em área experimental no município de Monte Carmelo (MG), com a avaliação da eficiência de aplicação hidropneumática com diferentes volumes de calda, 200 L ha-1 e 400 L ha-1 , duas pontas de pulverização jato cônico vazio (JA-01 e TVI-800075), presença/ausência de adjuvante agrícola na calda de aplicação, Cloridrato de Cartape na dose de 500 g i.a ha-1 , e Cartape + óleo de laranja, na dose de 75 mL 100 L-1 de calda. O uso do óleo de laranja interferiu na aplicação, alterando a densidade de gotas e amplitude relativa. O uso de gotas grossas é uma alternativa viável para a eficiência da aplicação em época de baixa umidade relativa do ar. O maior volume de calda aumentou a percentagem de cobertura e densidade de gotas no alvo.

Water magnetization and geoprocessing are increasingly utilized tools in weed management. Our objective was to study the influence of water magnetization on herbicide efficiency and to verify whether there is a relationship between control scores and the normalized difference vegetation index (NDVI). In the laboratory experiment, water was subjected to magnetization and evaluated with respect to four characteristics. In the field experiment, plots of Brachiaria grass were subjected to treatments in a factorial scheme (6 × 2 + 1). Six herbicidal factors (doses of glyphosate and glyphosate + 2,4-D) and the magnetization or absence of magnetization of the spray solution were evaluated and compared against the control treatment (without spraying). Weed control assessments were carried out six times. Images were obtained using an embedded multispectral camera to determine the NDVI values. Data related to water characteristics were analyzed using the t test. Weed control and NDVI data were subjected to analysis of variance and are presented in regression graphs. Dispersion analysis of NDVI data was performed according to the control scores. The magnetization process decreased the pH of the water and increased the surface tension, but it did not influence the control scores or the NDVI. As the glyphosate dose was increased, the control scores were higher and the NDVI values were lower. Magnetized water did not affect the biological efficiency of the herbicides, and there was a strong correlation between the control scores and the NDVI values.

Coffee production faces challenges due to the susceptibility of the crop to insects. Owing to the coffee leaf miner Leucoptera coffeella, which is one of the main insect pests, the technology for the application of phytosanitary measures becomes the main challenge for coffee growers. This study aimed to evaluate the effectiveness of coffee leaf miner control using different methods of application. The study was conducted in an experimental site in the municipality of Monte Carmelo -Minas Gerais. Spray depositions in different positions of the plant canopy and the effective control of coffee leaf miner were evaluated using the following application treatments: a hydropneumatic sprayer with varying spray volumes (200 and 400 L ha -1 ), two hollow-cone spray nozzles with the presence and absence of agricultural adjuvant, and electrostatic application using a spray volume of 200 L ha -1 with and without spray adjuvant. The addition of an adjuvant to the spray did not influence coffee leaf miner control; in contrast, a spray volume of 200 L ha -1 combined with the application of coarse droplets was efficient in the management of insect pest. The reduction in the rate of the application using coarse droplets increased the operational capacity and reduced spray drift potential.

The use of resistant cultivars is one of the strategies for downy mildew management. The objective of this study was to evaluate the vertical and horizontal resistance of F5:6 progenies of carotenoidbiofortified lettuce to virulence phenotypes of Bremia lactucae 63/63/51/00, 63/31/19/00 and 63/63/19/00. The experimental design was completely randomized and subdivided into plots that were evaluated over time. In the plots, 12 genotypes of lettuce were used, and the subplots were monitored over time (7th to the 18th day after inoculation). For each virulence phenotypes of Bremia lactucae, a separate experiment was performed with three replicates. To select resistant genotypes, plants were inoculated with distilled water, sporangia removed from infected tissues and Tween 20. The genotypes were evaluated when sporulation appeared on cotyledonary leaves of the susceptible cultivar Solaris, verifying the proportion of necrotic and sporulated plants. There was a correlation between genotypes and times for all virulence phenotypes evaluated. Genotypes UFU-189#2, UFU-206#1, UFU-215#3 and UFU-215#14 showed vertical resistance to virulence phenotypes 63/63/51/00, 63/31/19/00, and 63/63/19/00 of B. lactucae. Horizontal resistance levels were observed in genotype UFU 206#1 for virulence phenotypes 63/63/51/00 and 63/31/19/00; in genotype UFU-66#7 for virulent phenotype 63/31/19/00; and in genotype UFU-215#10 for virulence phenotype 63/63/19/00.

Lack of cultivar adapted to the planting area, as the ideal harvest period undertakes the productive potential of cassava. The study was conducted to evaluate the influence of different harvest seasons on total production of fresh and dry weight of four cassava cultivars. The used cultivars were: Branca de Santa Catarina (BSC), IAC 13, IAC 14-18 and Fiber that they were planted on 09/20/11 at the headquarters of the Regional Center Valley Paranapanema Paulista Agency for Agribusiness Technology (APTA), in Assis, São Paulo. The experimental design was completely randomized in 4x6 (four cultivars and six harvest seasons) factorial schemes with four replicates, being 4, 8, 12, 16, 20 and 24 months after planting (MAP) the harvest season, totaling 24 treatments and 48 installments. The total production of fresh biomass (FB) and dry matter (DM) in tons per hectare of 12 plants per harvest season was evaluated. Regarding the production of FB as DM among cultivars was not observed significant differences between them. However, the cultivars showed accumulation of FB linearly. The best time to harvest in order to higher accumulation of DM occurred at 12 and 24 months, corresponding to the end of the first and second round of cassava cultivation, respectively.