Behavior of the black sigatoka (Mycosphaerella fijiensis Morelet), according to banana production system and area, Valverde Province, Dominican Republic

Abstract

Black sigatoka (Mycosphaerella fijiensis morelet) is the most limiting disease in the Dominican banana industry. The behavior of black sigatoka was evaluated in conventional (CS) and organic (OS) banana systems (CS and OS) in five locations (Cruce de Guayacanes, Guazumita, El Charco, Palo Amarillo and Los Cáceres, Valverde province). The following were measured: Evolutionary State (ES), youngest diseased leaf (JDL), youngest necrotic leaf (JNL), incubation period, development period; production variables: number of leaves at flowering (NLF), at harvest (NLH), pseudostem circumference, mother plant height, hands/bunch, leaf emission rate (LER); and area variables: temperature, precipitation, wind speed and irrigation water flow applied. Principal component analysis (PCA), correlations and Kruskal Wallis test were performed. Components 1 and 2 of the PCA explain 79 % of the variance in SC and 78 % in OS, and the relationship of the variables varies with the area, with the most common being the incidence of precipitation and irrigation water. The Kruskal Wallis test indicated highly significant differences between systems for irrigation water flow (p < 0.0001), in ES, JDL, NLH, JNL and LEF (p = 0.0399, 0.0042, 0.0001, < 0.0001 and 0.0001). There were no differences between systems for the other variables. The highest disease severity was recorded in Palo Amarillo and the disease was less severe in El Charco. Thus, the behavior of the disease does not depend on the production system but on management practices such as the irrigation flow supplied and the rainfall in the area.