Preventive application of Si to control orange rust on varieties of sugarcane seedlings cultivated under greenhouse conditions

Abstract

Among the several factors limiting sugarcane production, the occurrence and severity of diseases such as orange rust is one of the reason for replacing cultivars and the use of silicon (Si) can reduce the intensity of diseases caused by pathogens. This study was carried out to evaluate the effect of a preventive application of Si to suppress the intensity of orange rust caused by Puccinia kuehnii on sugarcane seedlings. Three experiments under house conditions have been conducted using a Randomized Block Design with two in a 2x5 factorial scheme (soil with and without Si application x five foliar treatments), with variety RB92-579 and SP81-3250, and a third study with 13 treatments (soil and foliar treatments) with variety SP-015503. RB92-579 showed higher dry mass without Si application in the soil whereas higher levels of Si content in plants and soil with soil treated with Si was verified. Foliar treatments showed higher values of height, dry mass, and Si uptake. The severity level of orange rust on SP81-3250 with soil treated with Si was lower than on untreated soil. SP-015503 showed a dry mass and Si uptake increase with foliar treatments, especially with silicic acid. K silicate and silicic acid showed lower severity of orange rust than the control and fungicide. Si was able to reduce the severity of orange rust and improve plant development even though it does not have effectiveness as a preventive treatment to control orange rust in one of the studied varieties.