The Most Effective Fungicides to Use on Your Lawn

Mother nature is full of wonders, but it's also responsible for many problems you might face with achieving your golf course lawn. Most frequently, you’ll find yourself tasked with eliminating weeds or pest control challenges. But, other organisms can damage your lawn.

Fungi are the most common parasites which cause plant disease. Preventing weeds, pests, and fungi from infesting your grass comes down to consistent lawn management and care. Healthy and strong grass is at far less risk of inviting in our fungal foes. Lawns are naturally full of fungal spores, which usually don’t cause any harm to your grass. However, certain conditions can cause these spores to germinate and lead to diseases like red thread and brown patch. Here are a few common causes of lawn fungus which you can easily prevent:

Underwatering or overwatering your lawn — Grass types like Bermuda only need about an inch of water during the summer months. For more lawn watering tips, check out our YouTube video:

 

 

Compacted soil — Remedy this by aerating your soil, perforating the grass with small holes to allow air, water, and nutrients to penetrate down to the roots.

Leaving the grass too long or cutting it too short — To achieve a perfect lawn, we recommend mowing the grass three times a week. You should cut off no more than a ⅓ of the grass’s entire length.

Too much fertilizer — Excess fertilizer can encourage weeds and fungi to grow as well as your grass.

Weather conditions — High humidity and cold, damp conditions can stimulate fungi growth.

      Aside from deploying preventative measures, lawn fungus can still make its way into your lawn. Before treatment, it’s essential to identify what you’re dealing with. Read on to find out how to spot common lawn fungi and the most effective fungicides to treat them.

      What Are Fungicides?

      Fungicides fall under the category of pesticides. They can prevent, kill or inhibit fungi growth but can’t be used against bacteria or viral diseases. Fungicides can be classified in these ways:

      • Contact fungicides, also known as protectants, aren’t absorbed by the plant and stick to leaf surfaces. This forms a barrier on the plant that stops the fungus from entering and damaging plant tissues.
      • The entire plant absorbs penetrants.
      • Preventative fungicides stop the fungus from reaching the plant, although they must come into direct contact with the fungus, so reapplication might be necessary.
      • Curative fungicides target the fungus after infection has begun, or the first symptoms are visible.

      Now you have a better understanding of the types of fungicides available, it’s time to identify the lawn fungus causing damage to your turf.

      How to Identify Common Lawn Fungal Diseases

      Fungal diseases are prevalent when your lawn suffers environmental stress. This varies according to grass-growing regions. Warm-season grasses become vulnerable when abnormally cool conditions slow their growth — and the opposite is true for cool-season grasses. Too much rain, drought, or overcast skies will affect your lawn’s ability to fight back against fungal diseases.

      We’ve compiled a list of some of the most common fungal lawn diseases for warm and cool-season grasses and how to identify them.

      Brown Patch Lawn Disease

       

      This is an easy one to look out for. Brown patch is caused by the fungus Rhizoctonia solani and is one of the most widespread lawn diseases. You’ll see circles of the dead, sunken grass which varies in size — from a few inches to several feet. The circle’s perimeter will appear light gray in periods of high humidity.

      The most vulnerable grass types are:

      • Perennial ryegrass
      • Tall fescue (and fine fescue grasses)
      • Bentgrass
      • Bermuda grass
      • Kentucky bluegrass
      • St. Augustine.

      In the spring and fall, warm or hot weather conditions are the times in which brown patch lawn disease is most likely to occur. Wet leaves, excess water, and over-fertilizing all contribute to the spread of brown patch lawn disease.

      Dollar Spot Lawn Disease

       

      This lawn disease starts with silver dollar-size circles that can spread up to six inches wide, merging eventually into large blocks. Your grass will start developing yellow spots with a brown border that look water-soaked. You might also notice cobweb-like growth in the grass in bright lighting.

      The most vulnerable grass types are:

      • Tall fescue (and fine fescue grasses)
      • Perennial ryegrass
      • Bentgrass
      • Centipede grass
      • Kentucky bluegrass
      • Bermuda grass
      • Zoysia grass.

      Dollar spot disease can develop from late spring to fall — favoring mild-to-warm temperatures. Excess moisture or too little moisture and under-fertilizing can leave grasses more susceptible to this disease.

      Red Thread Lawn Disease

      Photo taken by Pete Dernoeden, PhD

       

      Grass blades begin to wither from the tips as red or bleached-looking patches start to form. You’ll notice that reddish-pink threads bind together grass blades, and red spores will appear on your shoes or tools.

      The most vulnerable grass types are:

      • Fine fescue
      • Perennial ryegrass
      • Bluegrasses
      • Bentgrass.

      Red thread lawn disease prefers mild temperatures in early spring, also enjoying wet conditions. Under fertilizing, poor air circulation, shade, excess thatch, compacted soil, and wet leaves contribute to this condition.

      Rust Lawn Disease

       

      The clue is in the name. Rust lawn disease forms irregular patches of thinning grass, which develop yellow specks, becoming rust-colored. Orange spores cover grass blades — so like red thread, you’ll start noticing these spores on your tools, shoes, and mower.

      The most vulnerable grass types are:

      • Tall fescue (and fine fescue grasses)
      • Perennial ryegrass
      • Kentucky bluegrass
      • Zoysia grass
      • Bentgrass.

      Moderately warm or mild temperatures facilitate rust lawn disease, so early summer and fall are when your grass is most susceptible. Drought, hot weather, excessive moisture, too much shade, and under fertilizing are responsible.

      Snow Mold Lawn Disease

       

      Snow mold lawn disease begins with small, circular pinkish spots that can spread up to a foot in length. The grass blades become soaked with water, particularly under snow — turning red-brown. In the morning light, you’ll easily see white fungal threads that look like frost.

      The most vulnerable grass types are:

      • Tall fescues (and fine fescue grasses)
      • Bentgrass
      • Perennial ryegrass
      • Kentucky bluegrass.

      Cold temperatures in fall combined with a lot of rainfall allow snow mold to strike in winter. The excess nitrogen that comes with over-fertilization can leave grass more susceptible to this disease, along with poor drainage and too much shade.

      Of course, these aren’t the only lawn diseases out there. We recommend identifying your fungal infection before moving on to treatment and management.

      The Best Fungicides for Your Lawn — Syngenta Fungicides

      You’ve tried your best to maintain a healthy lawn, but sometimes pests, weeds, and fungi still find a way in. If that sounds like you, it’s time to bring out the lawn fungicides. But which ones do you choose? Luckily, we’ve got two highly-effective fungicides that directly target and mitigate lawn fungus in your grass — brought to you by esteemed manufacturer Syngenta.

      Caravan G — Insecticide and Fungicide

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      This is the best fungicide for your lawn if you have a pest problem and a potential fungal issue. Caravan G is a granular insecticide and fungicide which provides exceptional insect and fungus control with a single application. The two active ingredients (azoxystrobin and thiamethoxam), combined, target grubs, craneflies and chinch bugs to name a few. Lawn fungi controlled by Caravan G include brown patch, fairy ring, large patch, and more.

      This fungicide can provide grub control for an entire season and a month of preventative large patch control. Because this product combines an insecticide and fungicide, it’s more economical than applying two separate products — saving you time and money. Apply between May and July for the best results. Note that this is a preventative fungicide, so if you’re dealing with an active fungus outbreak, apply Headway G fungicide 28 days later.

      The product is safe for use on residential and commercial turfgrass and harmless to people and pets when used correctly.

      Application Tip: One bag of Caravan G covers between 10,700 - 15,000 sq ft. The best way to apply this insecticide/fungicide is with a broadcast spreader.

       

       

       

      Headway G — Fungicide Granular

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      Brought to you again by Syngenta, Headway G is a broad-coverage granular fungicide that targets a wide range of common lawn fungi. Brown patch, dollar sport, fairy ring and more can be mitigated with a single application. Headway G contains two broad-spectrum fungicides which work together to eliminate a vast range of lawn fungi. This kind of fungicide coverage often requires two or more products. Here you get it all in one.

      Safe for people and pets, save time and money — avoiding countless applications with multiple products.

      Application Tip: One bag of Headway G covers 8,500-15,000 sq ft. We recommend using a broadcast spreader to apply this product.

      Preventing and Targeting Lawn Fungi

      Keeping your grass in good condition helps prevent the onset of lawn fungi. Keep an eye on the weather, bearing in mind the circumstances fungi thrive. For example, use a home soil test kit to determine the pH level of your soil — most grasses require a neutral pH.

      Use grasses recommended for your region and ensure you fertilize properly (not too little or too much). Also, remember to dethatch your lawn and regularly aerate your grass to discourage pests and fungi. It might seem like a challenging routine, but if you want to achieve a perfect golf course lawn, you’ll need to be proactive.

      Golf Course Lawn can help you prevent and eliminate invasive lawn fungi. Browse our range of highly-effective insecticides and fungicides to get a healthy, vibrant lawn.