Leaves Changing Colour... How 'bout your lawn?

Submitted on September 2, 2015

As the leaves begin to change, temperatures get cooler and the days get shorter, you see various plants and wildlife reacting in preparation for winter. Just like any plant life, your lawn is a living, breathing oxygen-producing plant system that needs to be monitored. Sometimes at this time of year, even though temperatures have cooled down and hopefully more rainfall has started to happen, your lawn may not look as vibrant and healthy as it should. When looking at your lawn, is it green and healthy looking, or does it look dis-coloured and wilted? It could be a fall lawn disease. This article will briefly touch on some common diseases that show up on many lawns at this time of year. Powdery Mildew Disease  Powdery mildew disease is a fungus that lives in the soil thatch and dead leaves in your lawn all year round. It feeds by drawing valuable nutrients that help your stay lawn green and lush. Very often this disease is seen in yards with a lot of shade. Sometimes even without trees, privacy fences can create a shady environment that only becomes a potential issue during shorter daylight times of the year. Powdery Mildew thrives in these conditions especially when there is poor air circulation. How do you know if your lawn has powdery mildew? The telltale sign of powdery mildew is unmistakable. It basically looks as if someone painted your lawn with white paint. The whitish gray dusty powder that forms on the grass blades is caused by mycelia or the fungus produced by Powdery Mildew disease. Powdery Mildew Disease can be minimized by doing the following:

  • Increase air circulation and light penetration through pruning or thinning trees and shrubs.
  • Overseed with a shade tolerant seed mixture.
  • Raise mowing height as well as water deeply and infrequently to avoid drought stress.
  • Provide adequate fertility, while avoiding excessive nitrogen that can contribute to the disease. (If you are a Weed Man program customer, please talk to your local franchise about the need for more fertilizer)
  • Aerate your lawn to increase water and air movement within the grass plants.

Red Thread Disease Red thread is a foliar disease occurring on taller mown grass during the cool, moist spring and fall timeframe, especially during long evening dew periods. Red thread takes its name from the antler-like structures the fungus produces on the tips of infected leaf blades, and it travels through lawns in the form of spores. When red thread is thriving, it literally looks like red/pink strands of thread are coming out of the tops of the grass blades. There are a number of conditions contributing to the development of this disease:

  • Poor soil fertility and turf grass nutrition.  (If you are a Weed Man program customer, please talk to your local franchise about the need for more fertilizer)
  • Excessive thatch layer can provide prime breeding grounds for the disease.
  • Lawns with high proportions of Kentucky bluegrass, perennial ryegrass and tall fescue are very susceptible to attack.
  • Limited air circulation and inadequate drainage enable the spread of the dreaded red thread.

Control of this largely cosmetic disease is achieved through modifying the lawn environment. Even with its undesirable appearance, the crowns and roots of the turf are not infected, so recovery and elimination is usually quite straight forward. Prevent/Control Red Thread Disease by doing the following:

  • Prune trees and other landscape shrubs above your lawn to improve air circulation and allow the penetration of sunlight.
  • Avoid watering lawns and landscape in the late afternoon or early evening to reduce overly high moisture levels.
  • Consistent application of fertilizer to build a stronger, healthier and more disease-resistant lawn. (If you are a Weed Man program customer, please talk to your local franchise about the need for more fertilizer)
  • Temporarily bag your grass clippings when mowing until disease symptoms subside.
  • Core aeration will reduce the thatch layer and improve water penetration in your lawn as well.

Rust Disease At this time of year, if you notice a powdery, rusty coloured dust on your shoes after you cut the grass or play catch with the kids on the lawn, your grass may be infected with Rust Disease. Rust is an orange/yellow powder that forms on the tips of your lawn’s grass blades. And while it is not a serious threat to your lawn’s health, it is a fairly common disease occurring in late summer and early fall. This powder like substance easily rubs off on shoes, hands, animal paws, lawnmowers, and almost anything else which come in contact with it. It is most prevalent during cloudy and overcast weather, or during times of high humidity such as late summer when dew accumulates overnight on your lawn. Additionally, transition periods from cool and wet weather to hot and dry temperatures create ideal conditions for rust to develop. Rust generally attacks slow growing or stressed grass, which is often the case in the late summer months as the season begins to change and lawn growth slows down. Low grass fertility, hot weather and limited water availability contribute to stifling your grass’ growth and create an environment where rust can thrive. It is most common in Kentucky bluegrass and perennial rye grass lawns. While rust is not a cause for serious concern for homeowners since it does not kill the grass, it does weaken and add unnecessary stress to your lawn. This makes your lawn susceptible to other diseases which prey on distressed lawns. Good lawn maintenance practices – fertilization, regular mowing at an increased height and irrigation - will help improve your lawn’s health and help ward off this unsightly problem. When watering your lawn be sure to do so deeply but do not overdo it. Be sure to water early in the day so the water has time to sink in and doesn’t remain on the grass blades. Excess moisture can increase the chance for rust and other unwanted diseases. Some of the basic maintenance actions you can take to promote a healthy, rust and disease-free lawn include:

  • Fertilize as necessary to promote recovery (If you are a Weed Man program customer, please talk to your local franchise about the need for more fertilizer)
  • Water your lawn deeply and consistently.
  • Mow regularly and increase the mowing height for the lawn.
  • Consider Over Seeding.
  • Have a professional lawn aeration done.
  • Make sure your lawn has proper drainage and water circulation.

If you follow these steps on a consistent basis, you should shake the rust right out of your lawn, keeping it healthy and looking good. So remember, as the leaves start to change colour and fall, check the colour of your lawn and make sure it’s healthy heading into the fall & winter months ahead. Because identifying lawn diseases can be tricky, we recommend you contact your local Weed Man professional to conduct a free inspection of your lawn for an accurate diagnosis.


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