Optimal period for the evaluation of sugarcane orange rust disease in Cuba

The results of 12 sugarcane cultivars evaluated against sugarcane orange rust disease on the plant strain in two planting cycles (spring and cold) are shown. The number of pustules and the length of the most frequent pustule on leaves +1, +3, +5 and +7 at three, four, five, six and seven months of age were evaluated in a 2 cm2 sampling station. The percentage of area occupied by pustules was calculated using a mathematical expression. Data were processed through the SPSS statistical package and analysis of variance and Tukey's test were performed for the sources of variation: leaves, evaluation dates, cultivars and cycles. The results showed differences for all sources of variation, leading to the conclusion that, although the affectations are not of great intensity, there are differences in the manifestation of symptoms in the different cultivars, and that studies to determine the presence of the disease and resistance of the genotypes should be carried out with cold plantings, also evaluating the +3 or +5 leaf when the crop is three and five months old.