The witches' broom of the cupuaçu is the main disease of the crop. In order to adjust the methodology for the studies of epidemiological parameters, inoculation test studies were performed. The experimental design used was a randomized block design with seven treatments, three repetitions, and five useful plants per plot. The seedlings were inoculated at three months of age in greenhouse conditions on the young purple colored shoots using the following treatments: 1. block of water-agar containing spores of C. perniciosa, 2. concentrations of 75,000, 3. concentration of 250,000, 4. concentration of 500,000, 5. concentration of 1,000,000 basidiospores of C. perniciosa/ml, respectively, 6 Tween 20 at 0.01% (T1), 7. block of water-agar (T2). Climatic data of temperature and relative humidity were noted. Evaluations were made 21 days after inoculation. Treatments 1, 4 and 5 were found to provide 100% infection while the controls remained healthy. Based on the results, treatment 4 was selected for epidemiological parameter studies.
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