Adubação foliar, etilfosfonato de cobre e fungicidas no manejo da mancha de phoma do cafeeiro

Abstract

Coffee is one of the cultures that most stands out in Brazil, in social and economic scope. There are several obstacles to coffee production, especially diseases. Phoma stain, a disease whose etiological agent is the fungus Phoma tarda, causes considerable losses in coffee plantations at high altitudes. The losses can cause a reduction in productivity of up to 43%, due to the fall of leaves, dryness of branches and mummification of fruits. The search for products that are effective in controlling the disease, replacing the fungicides registered for their management, and that have a low impact on the environment, has been growing gradually. Therefore, the objective of the present work was to evaluate the effect of the application of leaf nutrients associated with copper ethylphosphonate and fungicides in the management of coffee phoma spot. Two experiments were carried out, one in field conditions and the other in a greenhouse. The field experiment was installed at Fazenda Boqueirão, in the municipality of Campos Gerais, Minas Gerais, at an altitude of approximately 1112 m. The experiment was carried out from July 2017 to July 2019, referring to two harvests (2017/2018; 2018/2019). The crop is formed with the cultivar Catuaí Vermelho IAC 144 (Coffea arabica L.), aged 15 years. The experimental design used was randomized blocks (DBC) with 4 blocks, 8 treatments associated or not with leaf nutrition (presence and absence), thus constituting an 8x2 factorial scheme. The treatments were: T1 (control); T2 (copper ethylphosphonate-EFCu); T3 (fosetyl-Al-FAl); T4 (boscalida- BOS); T5 (iprodiona- IPRO); T6 (EFCu + FAl); T7 (EFCu + BOS); T8 (EFCu + IPRO). The incidence of the disease, the percentage of mummified pellets, defoliation, productivity, the physical appearance of the grains and the leaf nutrient content were evaluated. The incidence of the disease was lower in all treatments associated with nutrition, with the exception of EFCu + FAl for the 2017/2018 crop. In the 2018/2019 harvest, there was no difference between treatments compared to the control. For mummified pellets, all treatments differed from the control, and the application of EFCu + FAl, EFCu + BOS and EFCu + IPRO resulted in a lower percentage of mummified pellets in the two evaluated harvests. Regarding productivity, the BOS, EFCu + IPRO, EFCu + BOS and EFCu + FAl treatments provided an increase of 6, 8, 12 and 13 bags / ha, respectively. Regarding the physical aspect of the grains, nutrition was efficient in increasing the percentage of grains in the largest sieves. There was an increase in the levels of calcium (Ca), magnesium (Mg), boron (B), iron (Fe), manganese (Mn) and zinc (Zn) in the area under the effect of leaf nutrition. The greenhouse experiment was conducted from January to July 2019, at the Department of Phytopathology at the Federal University of Lavras, Lavras, Minas Gerais. Coffee seedlings of the cultivar Catuaí Vermelho IAC 144, 4 months old, were used. The experimental design used was randomized blocks (DBC), with 4 replicates and 4 plants per plot. The treatments were: T1 (control); T2 (copper ethylphosphonate-EFCu); T3 (boscalida- BOS); T4 (EFCu + BOS), chosen because they present better results of phoma spot control in field conditions. The enzymatic activity of phenylalanine ammonium lyase (PAL), peroxidase (POX), the content of phenolic compounds and lignin, the content of chlorophyll a and b, and the height of plants were evaluated. There was no difference in the levels of lignin, chlorophyll, phenolic compounds and plant height. The EFCu treatment promoted an increase in POX activity. Greater PAL activity was quantified in the treatment with BOS.