Using a copper-polyphenols compound as an alternative for coffee leaf rust

• Ano de defesa: 2024
• Autor(a) principal: Castro, Henara Valéria Miranda
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Fitopatologia
• Palavras-chave em Português: Coffea arabica; Café - Doenças e pragas; Ferrugem-do-cafeeiro - Controle; Patógenos de plantas; Histopatologia; Fotossíntese; CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA
• Link de acesso: https://locus.ufv.br/handle/123456789/34320; https://doi.org/10.47328/ufvbbt.2024.577

Epidemics of coffee leaf rust (CLR), caused by the biotrophic fungus Hemileia vastatrix, greatly contributes to lower the production of fruit berries. This study investigated the potential of using Mantus® [nitrogen (1%) and copper (20%) complexed with a plant-derived pool of polyphenols (10%)] to hamper the infection process of H. vastatrix in coffee leaves. This product will be referred to copper-polyphenols compound (CPC) hereafter. A 2 × 2 factorial experiment was arranged in a completely randomized design with four replications (one plant) per sampling time. The factors studied were plants sprayed with water (control), CPC, and fungicide (dicopper chloride trihydroxide) that were non-inoculated or inoculated with H. vastatrix. In comparison to the control treatment, urediniospores germination was significantly reduced by 59 and 99% for the CPC (rate of 1 mL/L) and fungicide treatments respectively. Urediniospores did not germinate after being exposed to the rates of 2.5, 5, 10, and 15 mL of CPC/L. The CLR severity (92-99% from 22 to 35 days after inoculation) and the area under coffee leaf rust progress curve (98 to 99%) were significantly lower for plants from CPC and fungicide treatments compared to plants from the control treatment. The incubation period (days) significantly increased by 46 and 53% for CPC and fungicide treatments, respectively, compared to the control treatment. The latent period (days) and the intensity of fungal sporulation were significantly higher by 40% and lower by 55%, respectively, for CPC treatment compared to the control treatment. For the CPC treatment, significant decreases of 45 and 28% were obtained for the area of uredosporic sorus and the number of uredosporic sori per cm2 of leaf and the area (µm2) of uredosporic sorus, respectively, compared to the control treatment. The production of urediniospores per cm2 of leaf was significantly lower by 96 and 99% for CPC and fungicide treatments, respectively, compared to the control treatment. At the physiological level, the CPC-sprayed and infected plants displayed a better photosynthetic performance (greater values for the maximum photochemical efficiency of photosystem II parameter) linked to the preservation of photosynthetic pigments (chlorophyll a+b and carotenoids) compared to water-sprayed and infected ones. In conclusion, the CPC showed great potential to be used for CLR control considering its effect to affect some components of coffee resistance and variables related to the fungal infection process. It is noteworthy in this context that besides the effect of Cu contained in the CPC against the germination of urediniospores from H. vastatrix, defense reactions could be boosted in coffee leaves to hamper the colonization of leaf tissues by fungal hyphae. Considering a field coffee-growing condition, the use of CPC could contribute to lowering the CLR epidemic rate and be considered in an integrated disease management program. Keywords: Coffea arabica; Biotrophic pathogen; Histopathology; Cell defense reactions; Photosynthesis.