Evaluación de enfermedades en plantas de café en un sistema agroforestal con diferentes niveles de sombra en el cantón Santa Ana

Abstract

In Ecuador, Arabica coffee (Coffea arabica L.) is cultivated in agroforestry systems (AFS). Although it has been demonstrated that shade affects disease intensity in coffee plantations, this response is still unknown in the country. The research was conducted in a coffee plantation of the Sarchimor variety (C. arabica) located in Santa Ana, Manabí, Ecuador, at an altitude of 380 meters above sea level, and associated with 70 tree species from the dry forest (fruit and forest species). The aim was to evaluate the effect of shade on the incidence and severity of coffee leaf rust, cercospora leaf spot, and thread blight in coffee plants under four levels (%) of shade, i.e., S0 (0%, used as a control), S1 (1-30%), S2 (31-50%), and S3 (51-60%). The diseases were evaluated in the lower (LE), middle (ME), and upper (UE) canopy of five plants per shade level, every fifteen days over a year. The data were integrated as the Area Under the Disease Progress Curve (AUDPC) and analyzed using an ANOVA. Finally, means were compared using the non-parametric Kruskal-Wallis test (p ≤ 0.05). Structures observed and identified from symptomatic aerial tissues, such as uredospores in pustules, conidiophores and conidia in lesions, and mycelium, basidia, and basidiospores on branches and leaves, corresponded to coffee leaf rust, cercospora leaf spot, and thread blight, respectively. Although the intensity of each disease varied over time, incidence was the variable least affected in all three diseases compared to severity. For example, the incidence of thread blight was affected by shade in the upper stratum. Meanwhile, the severity of coffee leaf rust and cercospora leaf spot were affected differently, regardless of the stratum analyzed. It appears that, while the severity of coffee leaf rust is reduced in full sun, thread blight, and cercospora leaf spot increase at low shade levels (1-30%).