As the season transitions into early autumn, it might appear that the responsibilities of lawn maintenance have dwindled. However, the cooling air doesn’t signal the end of your duties. The truth is, the fall season presents several challenges that can compromise the vitality of your lawn.
With the shift in weather patterns, it’s crucial to keep a vigilant eye out for any signs of distress. “As warm-season grasses slow their growth in response to environmental signals like cooler nights and shorter days, they enter a phase of recovery from the summer’s rigors,” explains Clint Waltz, a PhD and turfgrass specialist at the University of Georgia’s Turfgrass and Education Center.
Here are some of the prevalent issues that can affect your lawn during the autumn, along with solutions to maintain its health over time:
Contrary to many other issues, this one is entirely within your control. Even though the frequency of mowing may decrease during the fall due to reduced vertical growth, it’s still essential to maintain the correct mowing height for your specific grass type and local climate. Just like any plant, grass requires photosynthesis to produce food. Cutting too short can stress the grass, leading to thinning and creating room for weeds to germinate. “The health of your turfgrass and its root development are directly tied to the mowing height and root depth,” Waltz advises.
For instance, in the southeastern regions, zoysiagrass should be kept at a height of around 1 ½ inches, whereas St. Augustinegrass should be maintained at 3 to 4 inches. If you’re unsure about the type of grass you have, reach out to your local university cooperative extension service for assistance in identifying it and determining the appropriate mowing height.
Scot Nelson / Flickr / Public domain
Turfgrass fungi are a constant presence, but when conditions are right, such as prolonged humidity and cooler temperatures, diseases can thrive. One of the most widespread diseases is large patch (Rhizoconia solani), characterized by round, stained patches that can range from a few inches to several feet in diameter. This disease is particularly harsh on St. Augustinegrass, centipedegrass, and zoysiagrass. If left untreated, affected grasses may struggle to recover before winter, resulting in a delayed greening in the spring, according to Waltz.
Factors such as excessive fertilization in the fall, poor drainage, over-irrigation, or heavy rains from tropical storms can exacerbate the spread of this disease. While it’s typically not fatal, it’s important to monitor the weather and consider applying fungicide a few days to a week before conditions become conducive to disease development. Always adhere to the label instructions.
Even if you’re already witnessing symptoms of infection, applying fungicide now can halt the disease’s progression, prevent further spread, and offer about four weeks of protection. Additionally, adjust your lawn care routines, such as maintaining the proper mowing height, to deter its growth, Waltz recommends.
This same fungus is also responsible for brown patch in cool-season grasses like tall fescue, bluegrass, and ryegrass. These grasses can sometimes overcome the disease due to their active growth phase in the fall, though fungicides may still be recommended as the disease can kill these grasses, Waltz notes.
Dollar spot (Clarireedia jacksonii, previously known as Sclerotinia homoeocarpa) is a leaf disease affecting both cool- and warm-season grasses. It presents as small, whitish or tan spots that can grow to the size of a soup can. In the morning, you may also notice a fuzzy, spiderweb-like mycelium on dew-covered grass, Waltz explains.
Overfertilization, prolonged leaf wetness, and thatch buildup can contribute to its development. Adjust your lawn care practices, such as maintaining the correct mowing height and avoiding over-irrigation, and apply fungicide according to the label instructions, Waltz advises.
Fall armyworms (Spodotera frugiperda) are unable to survive winters in much of the southeastern United States. Instead, the moths travel on air currents or tropical storms originating from Central and South America, southern Florida, and southern Texas. Their populations can vary widely depending on weather conditions, with some years seeing higher numbers.
The adult moths, which are gray and about 1 ½ inches wide, are not the primary concern. The issue arises when they lay eggs, which hatch into larvae or caterpillars that voraciously consume your grass. These caterpillars are initially pale and small with a black head, but they grow to be 1 ¼ to 1 ½ inches long and can be green to nearly black with stripes. They feed at any time of day, and with large enough numbers, you may even hear their chewing, Waltz says.
Take immediate action upon spotting these pests, as they can devastate your lawn overnight. Use an insecticide containing carbaryl or bifenthrin. Choose a spray for the best coverage on the leaf surface, and follow all label instructions. If another generation appears, consider re-treatment, Waltz suggests.
White grubs are the larvae of various beetle species, including Japanese beetles, May and June beetles, and masked chafers. Initially, you might not notice them, but if your lawn becomes loose enough to be easily lifted from the soil, white grubs could be the cause. You may also observe wildlife, such as crows, armadillos, skunks, or raccoons, digging in your lawn to feed on the grubs.
Take action if you can easily pull up the turf and see plump, C-shaped white to dirty-white grubs with brownish heads and legs. While there are “curative” products available, they are not as effective as using a preventive insecticide in the spring. Apply a season-long preventive in the spring, adhering to the label instructions, Waltz advises.
