Wheat blast is one of the most important and devastating fungal diseases of wheat in South America, South‐east Asia, and now in southern Africa. The disease can reduce grain yield by up to 70% and is best controlled using integrated disease management strategies. The difficulty in disease management is compounded by the lack of durable host resistance and the ineffectiveness of fungicide sprays. New succinate dehydrogenase inhibitor (SDHI) fungicides were recently introduced for the management of wheat diseases. Brazilian field populations of the wheat blast pathogen Pyricularia oryzae Triticum lineage (PoTl) sampled from different geographical regions in 2012 and 2018 were shown to be resistant to both QoI (strobilurin) and DMI (azole) fungicides. The main objective of the current study was to determine the SDHI baseline sensitivity in these populations. Moderate levels of SDHI resistance were detected in five out of the six field populations sampled in 2012 and in most of the strains isolated in 2018. No association was found between target site mutations in the sdhB, sdhC, and sdhD genes and the levels of SDHI resistance, indicating that a pre‐existing resistance mechanism not associated with target site mutations is probably present in Brazilian wheat blast populations.

A diagrammatic scale with six levels (0.1-3.0; 3.1-6.0; 6.1-12.0; 12.1-18.0;18.1-30.0; 30.1-49.0%) was developed, compared, and evaluated along with two other scales to measure the severity of brown eye spots in coffee trees leaves. The scale was designed based on two others already in use in order to increase the efficiency of evaluation and for estimation values to approach as close as possible to their actual values. Two evaluations were performed using each of the three diagrammatic scales and one was performed without a diagrammatic scale, in seven day intervals. Using the proposed scale, the evaluators demonstrated better precision levels, accuracy, reproducibility, and repeatability in the estimations, when compared to the evaluators who did not use the diagrammatic scale, or who used existing scales. The proposed diagrammatic scale provided a reliable estimation to evaluate brown eye spot severity on coffee tree leaves.

RESUMOObjetivou-se, no presente trabalho, avaliar o efeito de épocas de irrigação e de parcelamentos de adubação sobre a produtividade do cafeeiro. O delineamento experimental utilizado foi em blocos casualizados com parcelas subdividas em faixas. O experimento foi composto por 4 blocos (repetições), cada bloco foi dividido em 4 parcelas, que receberam o efeito de diferentes parcelamentos de adubação (4, 12, 24 e 36 aplicações de fertilizantes), as parcelas foram subdivididas em 5 subparcelas, correspondentes às diferentes épocas de irrigação: "A" entre 01/06 e 30/09, "B" entre 15/07 e 30/09, "C" de 01 a 30/09, "D" entre 01/06 e 30/09 com adubação manual e "E" não irrigada. Promoveu-se análise de variância sobre os dados de produtividade, identificando-se que houve efeito apenas do fator épocas de irrigação sobre a mesma. O teste de comparação de médias possibilitou concluir que a irrigação entre 01/06 e 30/09, seja com o uso de fertirrigação ou com aplicação manual de fertilizantes, proporcionou as melhores médias de produtividade. Termos para indexação:Coffea arábica, quando irrigar, fertirrigação. ABSTRACTThis work aimed to evaluate the irrigation time and fertilizer splitting effects on coffee crop productivity. Random blocks with parcels subdivided into strips were the experimental design applied. The blocks had four replications and were divided into four plots. These plots (4, 12, 24 and 36 fertilizer applications) were subdivided into five subplots associated to different irrigation times: "A" between 06/01 and 09/30, "B" between 07/15 and 09/30, "C" between 09/01 and 09/30, "D" between 06/01 and 09/30 with manual application of fertilizer and "E" without irrigation. Analysis of variance was applied to evaluate the coffee crop productivity, which showed that only the irrigation time factor was effective. The mean comparison test allowed concluding that irrigation between 06/01 and 09/30, with fertigation or with manual application of fertilizer, produced the best productivity means. INTRODUÇÃOA cafeicultura é uma atividade importante para a economia brasileira, com significativa contribuição para a balança comercial. A produtividade do cafeeiro é fortemente influenciada pelo suprimento adequado de água e nutrientes para as plantas. Com a expansão da cafeicultura irrigada torna-se necessário desenvolver pesquisas que objetivem avaliar a viabilidade técnica e econômica dessa prática para as diversas regiões produtoras.Fernandes & Drumond (2002) relataram a obtenção de bons resultados de produtividade com a adoção da 1 Parte da tese de doutorado do primeiro autor 2 Engenheiro Agrícola, Doutor em Recursos Hídricos -Departamento de Engenharia/DEG -Setor de Engenharia de Água e Solo -Universidade Federal de Lavras/UFLA -Cx. P. 3037 -37200-000 -Lavras, MG -coelho@ufla.br 3 Engenheiro Agrônomo, Doutor, Pesquisador -Departamento de Engenharia/DEG -Universidade Federal de Lavras/UFLA -Cx. P. 3037 -37200-000 -Lavras, MG -marciano@ufla.br -Bolsista CNPq 4 Engenheira Agrícola, Doutora -Departamento de Engenharia/DEG...

Wheat blast, caused by Pyricularia oryzae Triticum (PoT) lineage, is a major constraint to wheat production, mainly in the tropics of Brazil where severe epidemics are more frequent. We analyzed disease and wheat yield data from 42 uniform field trials conducted during nine years (2012 to 2020) in order to assess whether the percent control and yield response were influenced by fungicide type, region (tropical or subtropical), and year. Six treatments were selected, all evaluated in at least 19 trials. Two fungicides were applied as solo active ingredients: MANCozeb, and TEBUconazole, and four were premixes: AZOXystrobin + TEBU, TriFLoXystrobin + PROThioconazole, TFLX + TEBU, and PYRAclostrobin + EPOXiconazole. Percent control, calculated from back-transforming estimates by a meta-analysis network model fitted to the log of the means, ranged from 43% to 58%, with all but PYRA + EPOX showing efficacy greater than 52% on average, not differing among them. The variation in both efficacy and yield response was explained by region and all but TEBU performed better in the subtropics than in the tropics. Yield response from using three sequential sprays was around two times greater in the subtropics (319 to 532 kg/ha) than in the tropics (149 to 241.3 kg/ha). No significant decline in fungicide efficacy or yield response was observed in nine years of study for any of the fungicides. Our results reinforce the need to improve control by adopting an integrated management approach in the tropics given the poorer performance and lower profitability, especially for the premixes, than in the subtropics.

Incidence of rust (caused by Hemileia vastatrix) and brown eye spot (caused by Cercospora coffeicola) of coffee was evaluated for 2 years in southern Minas Gerais, Brazil, in a center-pivot-irrigated coffee crop with different water application levels. Treatments consisted of six water levels of 0 (nonirrigated), 60, 80, 100, 120, and 140% applied according to class A evaporation pan (CAE). Progress of disease was influenced significantly by different water levels; the highest incidence of rust occurred with lower water levels—0 (nonirrigated), 60, and 80% CAE—whereas the lowest incidence was detected with larger water levels: 120 and 140% CAE. There was one peak of rust incidence in August. The highest incidence of brown eye spot occurred with water levels of 100 and 140% CAE and the lowest incidence was found in the nonirrigated treatment. Two incidence peaks occurred in March and June. This study identified that irrigation methods and water levels can decisively affect the epidemiological behavior of diseases and, therefore, their management.