A few rust calls are starting to trickle in, which is typical at this time of the year. Rust symptoms are reddish-orange lesions or spots on the leaf blades and a rust-colored powder that you can rub off with your fingers. Rust will rarely kill a turf area, but it can thin a turf stand especially this year when it will probably stay active well into September. Rust is most common on slow-growing, under-fertilized lawns. Even though a wide variety of fungicides will control rust, the best method to minimize this disease is to fertilize and now is the best time to fertilize. See the accompanying Turf Tip on fertilizing turf in September. reducing rust problems. Be sure to water in the fertilizer regardless of your application date.