What Is Lawn Rust?
If you look closely at the blades of grass on your lawn and notice an orange discoloration, you have identified what lawn care experts call ‘Rust’. Lawn rust can wreck havoc on lawns in Pennsylvania because Rust is found on perennial ryegrass, Kentucky bluegrass, and tall fescue, which are the three most common grass types.
Lawn Rust is a fungus that can easily be spread by wind, contact (blades touching one another), animals, and insects. This disease prefers the shade, but also heat and humidity. Unlike many other fungal lawn diseases, it grows well in soil that is low in nitrogen.
Rust reduces the ability of grass to undergo photosynthesis, and in photosynthesis, plants make sugar which fuels growth. When they are unable to produce the sugars necessary for growth, grass starts to die.
Identifying Lawn Rust
If you have a problem area on your lawn that you suspect has rust, pick up a blade of grass and inspect it. Spotting an early rust infection is key. The grass blades will have small, yellow discoloration dots. If the disease is not treated fast, the yellow dots will rupture and spread an almost powdery rust colored substance across the blades of grass.
Severe lawn rust will make the lawn turn brown and the grass will become matted down and bunched together. Some people might confuse this with thatch, when in fact this is a fungal disease.
Preventing Lawn Rust
Since rust thrives in wet, humid conditions, having soil that drains properly is key. When we have a summer like we did this year in 2018, where it rained so much, preventing lawn rust is extremely challenging. The best way to prevent rust is keeping your lawn rich in Nitrogen, by fertilizing in the Spring and Fall. Aeration will help your lawn drain better.
Hopefully next year we do not get as much rain frequency, because consistent wet and humid conditions are a breeding ground for Rust. Ideally, your lawn should be watered once a week, for a long period that really soaks the lawn.