As the leaves begin to fall and the air turns crisp, it’s easy to assume that lawn maintenance duties are on hold until spring. However, this isn’t the case. With the drop in temperatures, your lawn may face several seasonal perils that could compromise its vitality.
As seasons shift, vigilance becomes key. “Warm-season grasses, in response to the cooler night air and shorter days, slow their growth, whereas cool-season grasses are grappling with the residual stress of summer,” explains Clint Waltz, a PhD and turfgrass expert at the University of Georgia’s Turfgrass and Education Center.
Here’s a rundown of the typical fall lawn dangers and practical strategies to combat them, ensuring your lawn remains robust throughout the year:
Contrary to other issues, this is a factor you can manage. While mowing frequency may decrease during the fall due to reduced vertical growth, maintaining the right height for your grass type is crucial. Just as plants require photosynthesis to produce food, grass needs this process to thrive. Cutting too short can lead to stress and thinning, paving the way for weed seeds to take root. “Turfgrass health and root development are intimately linked to mowing height and root depth,” emphasizes Waltz.
For instance, zoysiagrass in the Southeast often needs to be trimmed to around 1 ½ inches, whereas St. Augustinegrass should be kept at 3 to 4 inches. If grass species identification is a mystery, reach out to your local university’s cooperative extension service for assistance and recommendations on mowing heights.
Scot Nelson / Flickr / Public domain
While turfgrass fungi are a constant presence, disease strikes when the conditions are just right—typically, prolonged humidity and cooler temps. Large patch, caused by Rhizoconia solani, is a prevalent disease characterized by round, stained patches, affecting grasses like St. Augustine, centipedegrass, and zoysiagrass. The disease can prevent affected grasses from recovering before winter dormancy, leaving them slow to revive in the spring, Waltz warns.
Excessive fertilization, poor drainage, overwatering, or heavy rains can exacerbate this issue. Typically not fatal, this disease can be managed by applying fungicide a few days to a week before the conditions conducive to its growth are favorable. Be sure to adhere to all label instructions. Applying fungicide can also halt the disease, prevent further spread, and offer protection for about four weeks, as well as adjusting lawn care practices, Waltz advises.
This fungus is also responsible for brown patch in cool-season grasses, like tall fescue, bluegrass, and ryegrass. Although these grasses can often outgrow the disease due to their growth cycle, fungicides may be recommended as a precaution, especially if the disease can be lethal to these types, Waltz notes.
Dollar spot, caused by Clarireedia jacksonii, affects both warm- and cool-season grasses, presenting as small, whitish or tan spots that can grow as large as soup cans. Morning dew often reveals a spiderweb-like mycelium. Overfertilization, prolonged leaf wetness, and excessive thatch can contribute to its occurrence. Waltz suggests addressing these issues by maintaining proper mowing heights, avoiding overwatering, and applying fungicides according to the label.
Fall armyworms, known for their voracious appetites, are the larvae of moths that migrate from Central and South America. These pests can decimate your lawn overnight, so immediate action is crucial. Insecticides containing carbaryl or bifenthrin can be effective, with sprays offering the best coverage. Be sure to follow all label instructions and reapply if necessary, Waltz advises.
White grubs, the larvae of beetles like Japanese beetles and masked chafers, can be the silent destroyers of your lawn. They may not be noticeable at first, but if you can easily pull up the turf and see fat, C-shaped white to dirty-white grubs with brownish heads and legs, it’s time to act. Preventive measures, such as applying a seasonal insecticide in the spring, are more effective than curative treatments, Waltz suggests.
