Rust on Turfgrass: Management and Control

Rust is a pathogen that affects higher mowed turf. Outbreaks are most prevalent on home lawns and low-budget athletic fields, although symptoms can appear on professionally manicured grass and golf course roughs as well. Rust begins as little yellow spots on leaves and stems and progresses to the formation of elongated, reddish-brown or orange pustules. When going through contaminated regions, the spores commonly color the shoes and garments orange. When rust is severe, it destroys leaves and weakens plants. Turfgrass quality suffers as a result of low color and plant vigor. Rust lives in infected plants as latent mycelia and as teliospores, and it can spread to turf from infections on other grasses and woody ornamentals.

Development

Rust fungus spend the winter in live plant tissue, where they develop new spores in the spring. The wind spreads spores generated in the spring, summer, and fall, which germinate on the leaves and infect new tissue. For the spores to germinate and the illness to spread quickly, the leaves must be damp for extended periods of time. Rust infections are particularly severe in grass that is developing slowly due to poor care or harsh weather conditions. Rust formation is aided by low light intensity, insufficient fertilizer, drought stress, and infrequent mowing.

Cultural Control

Plant rust-resistant turfgrass cultivars wherever feasible to prevent disease damage. When planting cool-season turfs, if feasible, employ blends and combinations of various species and/or cultivars. In extremely darkened regions, plant shade-tolerant grasses and adjust mowing heights. To increase air flow and avoid prolonged leaf wetness, prune trees and eliminate unnecessary vegetation. Mow the lawn on a regular basis, removing no more than one-third of the leaves in a single mowing. To inhibit the spread of rust, collect and discard of clippings gathered from contaminated areas.

Fertilize the lawn to suit its nutritional requirements. Water deeply but rarely to promote deep roots and prevent drought stress and prolonged leaf wetness. Watering the lawn before or after dark is not recommended.

Chemical Control

Fungicides can be used to manage rust either preventively or curatively. During chilly and overcast weather, susceptible turfs should be checked for rust formation on a regular basis.