Incidência espacial da doença ferrugem (Hemileia vastatrix Berk. & Br.) em lavoura de café robusta amazônico e comportamento de diferentes clones para severidade durante período chuvoso no sul do Amazonas

Abstract

The coffee culture in Brazil has a great social function, in addition to economic income that enables the socioeconomic development of several regions. Some diseases can influence crop productivity. Among them, coffee rust (Hemileia vastatrix Berk. & Br.) stands out for causing large losses, which can cause losses of up to 50% in favorable climatic conditions. The objective was to evaluate the spatial incidence of the rust disease (H. vastatrix) in Amazon robusta coffee plantations and the behavior of different clones for severity during the rainy season in southern Amazonas. The percentage of incidence was determined according to the number of leaves with symptoms in relation to the total number of leaves collected. To express the incidence values, the descriptive statistics method was used. To estimate rust severity, a specific diagrammatic scale was used, with scores ranging from 1 to 7, based on the area of the lesion. The data obtained were submitted to analysis of variance and the means were compared using the Scott-Knott test at 5% probability. There were high values of incidence of coffee rust both between rows and between samplings, the values ranged between 9.04% and 27.20%. Low values of coffee rust severity were verified both between lines and between samplings, the values vary between 0.04% and 0.19%, in lines 11 and 06 respectively. The observed severity percentages are partly associated with the climatic conditions of the study region. During the evaluation period, mean temperature indices of 25.98ºC were verified, which constitutes a favorable value for the progress of the disease. During the sampling period, high rainfall values varied between maximum and minimum 231.6 mm and 139 mm, the precipitation values were favorable for the development of the disease. Regarding severity values, there were higher values in the genotypes: clone 12 (0.24%); BRS 1137 (0.15%); BRS 160 (0.13%), however, the severity values between genotypes, observed during the sample period, are considered low. The data reveal that even though the disease has a high incidence, it was observed in this study that the clonal seedlings of Amazonian Robusta behave as resistant and/or tolerant to H. vastatrix.