Epidemiologia e resistência do cafeeiro conilon à ferrugem

• Autor(a) principal: Capucho, Alexandre Sandri
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1038
• topic: Hemileia vastatrix; Coffea canephora; Controle químico; Hemileia vastatrix; Coffea canephora; Chemical control; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA

In recent years the rust in conilon coffee (Coffea canephora), caused by Hemileia vastatrix, has occurred in large epidemics in the field. Little is known about this pathosystem and from questions about the host, pathogen and environment of this interaction became interested in developing this work, which aimed to: 1) to determine what temperature and wetness periods that favor germination and infection of H. vastatrix in conilon coffee and characterize, in field conditions, the influence of variables macroclimatic the epidemic of disease, 2) develop and validate a diagrammatic scale for coffee rust, 3) characterize the horizontal resistance of the variety of genotypes Conilon Incaper Victoria 8142, grouping them into levels of resistance to three races of H. vastatrix, 4) evaluate the efficiency of triazole fungicides applied to the soil with supplementation in the control of leaf rust in conilon coffee and estimate the damage caused by disease is this coffee. Experiments in a completely randomized design were performed to determine the temperature and wetness periods favorable for germination and infectivity of H. vastatrix. Regression analysis was performed to model the data. The results showed that temperatures between 21.6 and 23.6°C and leaf wetness exceeding 24 hours is the most favorable condition for germination and infection of conilon by H. vastatrix. These results helped to develop the discriminant functions of the second objective of the thesis. To achieve this objective, the historical data of climate in three municipalities in the north of Espirito Santo and the disease severity data were used to create the discriminant functions. Historically the months of the year most favorable to the infection of H. vastatrix are from May to October. At these times the monthly average temperatures are mild (near 22°C) with high humidity (>80%), associated with low monthly precipitation (<50mm), but with leaf wetness. To create and validate a diagrammatic scale for coffee rust was collected and scanned diseased leaves of C. arabica Catuaí IAC144 and C. canephora clone 02. The scale was validated by ten raters. The severity of diseased leaves was estimated first without the use of the scale and then using the scale. Regression analysis and Lin s concordance correlation between the data estimated and actual severity showed that the precision and accuracy were significantly better using the scale. The data analysis also showed that the scale presented high reproducibility and can be used by several people in the same quantification of an experiment. To determine the quantitative resistance in seedlings of the variety Conilon Incaper Victoria 8142, we used the races I, II and XXIII of H. vastatrix in a completely randomized design. After inoculations eleven resistance components were evaluated: incubation and latent periods, spore production, leaf area lesioned, number of spores per leaf area lesioned, sporulated leaf area, number of spores per sporulated leaf area, severity scale using the proposed, infection frequency, total number of pustules and expansion rate of the lesions. The use of multivariate analysis discriminant and of cluster with the eleven components of resistance possible to determine four levels of resistance: resistant plants, moderately resistant, moderately susceptible and susceptible. The group of plants more resistant (resistant or moderately resistant) to three races of H. vastatrix were established by clones 3V and 5V of the variety. To test the efficiency of triazoles in the soil with or without supplementation leaf in the control of leaf rust, an experiment was conducted in randomized block design with eight treatments. Every 30 days leaves were collected from experimental plots to measure the incidence and severity of disease. The production was also measured in years of conducting the experiment. With these data were plotted curves of disease progress and calculated the area under the disease progress curve for incidence of the disease. The intensity data of disease and production were also used to estimate the damage caused by rust in conilon coffee clone 02. The weather during the experiment had several months to promote the development of rust. Two epidemics occurred during the experiment, with a typical peak occurred in July and another with an atypical peak in January. The treatments with the soil applications were effective in controlling the disease, however, jointly analyzing disease control and productivity, the best treatments were those who used or cipronazol flutriafol in the soil, with or without supplementation leaf. The damage caused by rust in conilon coffee clone 02 can reach 47% if not implemented measures to control the disease.