Field library

Brown Rust

Round to oval orange-brown pustules scattered randomly over the upper leaf surface, without the neat striping of yellow rust. It prefers warmer weather, 15 to 22°C, so it usually arrives later in the season than yellow rust and does less damage unless it reaches the flag leaf.

How to scout

Check the flag leaf and the leaf below it from early February. Brown rust on the flag leaf is what costs yield; on the lower leaves it matters far less.