"Rust disease", this fungus attacks the leaves begin to ripen in the form of spots such as the color of rust, red-brown. Beneaththe surface of the leaves are yellow spots. If the attacks hadspread to the entire leaf, the leaves will look dry. The disease isspread in several places in Indonesia, from lowlands to high, butdoes not cause significant harm. Attacks usually occur in plantsolder than 1 month.
Rust fungi have calincing host plant grass (Oxalis sp) commonlygrows at an altitude of more than 400 m, the spores are scatteredin the air. Spores were going to land when the air temperaturedifference at the top and the bottom is large enough. This eventusually takes place at midday. If in the late afternoon rain that makes the environment more cool and moist, the spores willmultiply and damage the corn crop.
Prevention is done by keeping the humidity of the environment around the plant (micro environment) so do not be too high. This rust fungus will proliferate optimally at temperatures around 16 -23oC, with 100% humidity. Suitable fungicides for control ismade from Benlete T-120, or bitertanol like Baycor 25 wp. The dose used depends on severity of the attack. Commonly used 2 gr or 2 cc / liter of water.
Sources: TRUBUS - TH XXV - JUNE 1994