Progress of yellow Sigatoka in Prata-anã cultivar in Sergipe

Abstract

The yellow Sigatoka whose causal agent is the pathogen Mycosphaerella musicola is endemic in all producing regions of banana, and favorable environmental conditions may decline production. The aim of this study was to evaluate the progress of the severity of the yellow Sigatoka in the Prata-anã cultivar at edaphoclimatic conditions of coastal tablelands of Sergipe. The area to evaluate the severity of yellow Sigatoka was located in the experimental field of Jorge Prado Sobral of Embrapa Tabuleiros Costeiros, in Nossa Senhora das Dores, Sergipe, Brazil. The severity of yellow Sigatoka was evaluated, every 30 days, from 60 to 420 days after planting (DAP), using a descriptive scale proposed by Stover (1971). After data collection of disease severity, the Infection Rate (IR) was determined by the time evaluation through a described formula proposed by Stover. The environmental variables as precipitation (mm/day) and minimum, mean and maximum temperature (°C) were recorded from experimental field weather station. Furthermore, the IR was correlated (Pearson) with these environmental variables and DAP. Therefore, the Sigatoka yellow progress curve in the Prata-anã cultivar was divided into two periods: 60 to 210 days (period 1) and 240 to 420 days (period 2). The progress curves for the two periods were analyzed using simple linear regression. In period 1 (60-210, DAP) the highest severity progress of the yellow Sigatoka evaluated occurs with the increasing of the minimum temperature and with decreasing of precipitation, on the other hand, in the second period (240-420, DAP) the greater severity progress occurs with the decrease in the mean temperature. In both periods occurs greater progress on the yellow Sigatoka in function of time (DAP). The results may help control strategies of yellow Sigatoka, such as planning chemical control along the production cycle as well as serve as a basis for the study of this disease in other cultivars that may be introduced in the region.