Epidemias de ferrugem asiática no Rio Grande do Sul explicadas pelo fenômeno ENOS e pela incidência da doença na entressafra

Abstract

The interference of climatic variability and number of Asian rust reports in the off-season on the epidemics of the disease was studied in the state of Rio Grande do Sul for 11 seasons. The disease occurrence was obtained from reports presented at Antirust Consortium and divided among the periods “season”, “off-season” and “whole year”. Data on the epidemics were tested for correlation, via linear and quadratic polynomial regression, with climate variables: rainfall, standardized precipitation index - SPI, Southern Oscillation Index - SOI and sea surface temperature anomaly - SST in the Tropical Pacific Ocean, and number of occurrences of the disease in the off-season. The indices that best explained the variation in disease occurrence for the period “whole year” were SST and SOI, and coefficients of determination (R2) were 0.94 and 0.59, respectively. Rust occurrences in the period “off-season” positively influenced the occurrence in the “season” period.