Comparing Partial Resistance toPuccinia sorghiand Applications of Fungicides for Controlling Common Rust on Sweet Corn

Abstract

Common rust, caused by Puccina sorghi, can be controlled on sweet corn (Zea mays) by host resistance or fungicides. Different levels of partial rust resistance in sweet corn hybrids and levels of fungicidal control were compared in field trials from 1987 to 1992. The level of control provided by partial resistance depended, in part, on the effectiveness of fungicides. In the absence of fungicidal control, rust severity on the resistant, moderately resistant, and moderately susceptible hybrids was 15, 40, and 60%, respectively, of the amount of rust on the susceptible hybrid. When fungicide applications reduced rust severity on the susceptible hybrid by half, severity on the resistant, moderately resistant, and moderately susceptible hybrids was about 20, 55, and 80% of that on the susceptible hybrid [...]