Related links............Cultural Problems
RUST is a fungus disease that resembles the rust on roses. When an infected leaf is rubbed, a rust colored powder will stain the fingers. It appears as small flecks on the leaves which turn into larger spots with reddish-brown pustules. It is important to keep the garden clean and irrigate rather than overhead water to control rust. Rust occurs most often in moist climates. If the disease does occur, the iris should be sprayed with a good fungicide combined with a sticker-spreader. Be sure the fungicide is a specific one for rust.
FUNGAL LEAF SPOT appears as small, watery ovals on the leaves. They may develop a reddish border. This disease saps the strength of the plant and causes weak leaves and blooms in addition to being unsightly. To prevent leaf spot the garden should be kept clean. Spray with Daconil, Benlate, or Zineb 75 at 3-week intervals.
-- Main.RPries - 2010-10-13