One of the most commonly asked questions for homeowners involves the topic of lawn disease control and fungicides. There are an abundance of fungicides to choose from if you suspect disease in your lawn. Selecting and applying a fungicide can be intimidating. This week, Sod U covers lawn disease control, the differences between systemic, contact, preventive and curative application rates and a few strategies you can use to make sure you tackle your lawn disease problem efficiently and effectively.
About Lawn Disease Control
As mentioned in our Lawn Disease Control blog, a lawn fungus must have three criteria to spread:
- a host, living or dead organic matter (thatch and leaves),
- the right environmental conditions such as shaded, moist areas to grow in,
- and a pathogen—a bacteria, virus or other microorganism that can carry disease.
If a fungus is present in your lawn, it will usually present itself in circular or irregular patterns of damage as seen in the below images. Common lawn diseases include brown patch, large patch, pythium blight, pink snow mold and summer patch. You can learn more about the various common lawn diseases and how to control them in Identifying Common Lawn Diseases.
Systemic vs. Contact Fungicides
There are two main categories of fungicides you will find in any lawn and garden or hardware store: systemic fungicides and contact fungicides. A contact fungicide, as its name implies, is a fungicide that kills fungus upon contact and lasts for about seven to ten days. A contact fungicide is good for applying on a disease before you have identified the exact type of fungus you may have. On the other hand, a systemic fungicide serves as a penetrant—it’s absorbed into the system of the plant—and can be used to suppress the fungus after infection. Both categories of fungicide are useful, but should be used strategically depending on the lawn disease situation you may have.
Preventive vs. Curative Fungicide Application Rates
Sod University believes an ounce of prevention is worth a pound of cure. Fungicides can be applied at two rates: preventively or curatively. Preventive rates are less than curative rates. Most bags or bottles of fungicide will instruct you on how much you should be applying, but generally speaking, curative rates are four to five times higher than preventive rates. If you are applying at a curative rate, meaning you already know you have a fungus in your lawn, you will be purchasing more product and spending more money on fungicide than you would applying at a preventive rate—you are trying to be safe and prevent lawn disease from happening in the first place. It is always good to go ahead and apply fungicide preventively so you don’t wind up spending more money.
Fungicide Strategies and Combined Chemistries
When it comes to the worst of disease problems in your lawn, sometimes one fungicide just doesn’t do the trick. Combining fungicide applications can seem dangerous or scary when it comes to your lawn. You don’t want to just mix anything, so talking to local lawn care professionals is never going to hurt. However, there are a variety of strategies you can use to apply fungicide and prevent or cure lawn disease. An unbeatable strategy consists of thoughtfully combining fungicide applications with different chemistries. It is not uncommon for a homeowner to be spending loads of money and time on a proven, trusted fungicide that doesn’t deliver the expected results. Combining fungicide applications with differing chemistries is a good way to tackle even the hardest of lawn disease problems. For example, the active ingredient in Heritage G is azoxystrobin. The active ingredients in Armada 50 WDG are triadimefon and trifloxystrobin. Applying Heritage at the recommended rate and then following up a week to ten days later with an application of Armada at the recommended rate is an excellent way to fight off lawn disease that has been hard to get rid of or appears year after year. Be sure to read the label on any chemical products you plan to purchase or apply to ensure you won’t damage your lawn. Follow application instructions on the bag. If you purchase a granular fungicide, use a walk-behind broadcast spreader, such as the one pictured below, to make the application process less difficult. A one to two gallon garden sprayer is also a helpful tool for applying liquid fungicides.
Here are our product suggestions for a systemic and liquid fungicide, as well as a broadcast spreader for granular fungicide and a two gallon tank sprayer for liquid fungicide if you don’t already have them at home:
If you’re a do-it-yourselfer and want to control or treat fungus on your own, keep these three things in mind when purchasing a fungicide:
- Do you need a contact or systemic fungicide?
- Are you looking to prevent or cure a fungus—or both?
- What overall strategy are you going to use?
It is also important to note that if you aren’t a do-it-yourselfer and plan to hire someone to take care of your lawn, you should ask your lawn care service, “What, if any, fungus control products do you include in your lawn care maintenance package?” because almost none of them include it. In fact, most lawn care maintenance packages include mowing, leaf removal, landscape maintenance, hedge and shrub trimming, etc.—but not any fungus prevention methods. You can read more about what to look for in a company that offers fungicide treatments in How to Choose a Company for Lawn Care Treatment. Fungus can be a huge, detrimental issue in your lawn. Be sure you are taking preventive measures to keep fungus out, or to remove it if your suspect a disease in your lawn now.
For more information on fungus, visit our Lawn Disease Control blog. Although it is now the beginning of December, fall lasts until December 21st. If you have a warm season lawn, be sure to check out Beware of Late Fall Fungus in Warm Season Lawns blog.