Not surprising…our weather conditions have been prime for rust fungus to form on lawns this year. Most commonly, rust is noticed during periods of slow growth. Our lawns typically go dormant during the summer months due to the lack of rain and also heat. This summer is the first in a very long time that we have had regular rain fall through the entire summer months and also cool temperatures. For the most part, non-irrigated lawns have kept their lovely green color all season. Though, the rate of growth has slowed down.
Rust is noticed during periods of slow growth because the rust is not being physically removed by regular mowing at a fast rate as it would be if the lawn were growing rapidly. Therefore, the rust has an opportunity to proliferate on the slower growing blade of grass.
Once conditions are right for the grass to begin growing more rapidly, the rust ‘problem’ will mitigate itself without any additional inputs. Conditions can be related to weather or nutrients.
Some may advise that an application of fertilizer will take care of the rust problem. And while it is true that applying fertilizer will probably increase the rate of growth, applying fertilizer may not be the appropriate thing to do. If the soil is holding enough nutrients already, then these additional nutrients may just runoff and pollute our environment. Also, given that it is the middle of summer and weather patterns can change—if we are headed into a prolonged period of hot or dry weather, then applying fertilizer will enhance the likely hood of either burning out your lawn or creating conditions that are appropriate to other fungus and disease outbreaks.
If it is time to fertilize, meaning that you are following a regular fertility regiment that is appropriate for your lawn care needs and it is simply time to apply the next application of fertilizer and the weather is appropriate to do so, then a slow release nitrogen product should diminish the signs of this disease.
Often, this disease is only aesthetic and will not be detrimental to your lawn’s long term health. Rust is not something that we would ever recommend applying a pesticide for. Once the rate of growth increases the grass will outgrow the disease cycle.