Let’s talk about an issue Ive been seeing a lot of lately with all the heavy rains. A condition called Iron Chlorosis, where the grass blades start to become pale yellow to almost white in sever cases. It’s simply a lack of nutrients in the lawn, mainly iron, causing the pale appearance. Many people can confuse chlorosis with a Nitrogen deficiency. However a nitrogen deficiency will leave the blades a more solid yellow color rather than pale. But we will talk about that at a later time.
There are a few different reasons why a lawn can become chlorotic. The most common reason is over watering. Either from running the irrigation system too long, of from too heavy of a rainfall. The excess amount of water will cause the nutrients to wash out of the lawn. If this is the case, a fertilizer containing iron or a sprayable iron treatment can help correct this issue. Always be careful when applying iron products because they will stain non target areas. Check the irrigation system to make sure its not the cause or any treatment will be in vain.
Another common cause is high phosphorus levels in the soil. If the pH level of the soil is too high, it will cause a distortion in the nutrient uptake of the turf leading to this pale color. If this is the case applying a 21-0-0, which is Sulfate if Ammonia, will help balance the pH of the soil, and give the turn some extra nutrients. 5 pounds per 1,000 sq feet is the normal rate for this, but could require a few treatments to get the pH to drop where it needs to be. Make sure to test the pH between treatments to make sure you don’t send it too far the other direction. The pH level for St Augustine you should aim for is 6.5.
With this, and any other issues you have, I recommend seeking the help of a Lawn Care Professional. They will have the products and equipment to properly take care of any issues you may have. If you decide to do it yourself, always remember : THE LABEL IS THE LAW! Make sure to careful read the label of any product you use to make sure its the correct product, and that you apply is correctly. It is against the law to use products outside of the parameters stated on the label.
I want to briefly touch on one more fungus since I’ve been getting a lot of calls on this one. The picture above is one of a disease called Slime Mold. Unlike the Grey leaf spot fungus and Dollar spot fungus, this one is very easy to deal with.
Slime Mold will suddenly appear in the lawn during the wet summer months. Small little black patches will appear only a few inches big. Ive had a lot of homeowners seeing this and freaking out asking if their lawn is going to die. I have a lot of people calling me thinking its some kind of insect eggs all over their lawn. If you see this in the lawn, there is no need to panic.
There is absolutely no need to treat Slime Mold with any kind of product. It is purely cosmetic and will not cause any damage to the turn. After mowing it will clear up. If you need a quick fix and want to gone immediately, a strong jet of water will knock it off.
Continuing with our talk about Fungus, we have to discuss Dollar Spot Fungus. Just like the Grey Leaf spot we talked about previously, we are seeing a lot of dollar spot fungus out there in lawns. As you can see pictured above, dollar spot fungus will appear scattered throughout the affected area of the lawn with no pattern. Where Grey leaf spot will be spread out in an area, dollar spot will be more concentrated to a smaller more condensed area.
Upon close inspection, you will see that the entire grass blade will be discolored straw colored blades, unlike the Grey Leaf Spot where there will be small oblong spots on the grass blades. Affected areas will start out in small silver dollar size (hence the name), but can spread up to 6 inches in the right conditions.
Dollar Spot Fungus is most common in areas with dry soil but wet air. So when we went a couple months without rain here in Florida, followed by a week straight of heavy rains, it created the perfect storm for this disease to thrive. The high level of humidity in Florida is also a contributing factor of dollar spot. The best way to prevent this disease (barring extreme conditions from Mother Nature), would be to irrigate properly. are sure you water long enough to keep the soil moist. Keeping the lawn from going in and out of drought is key (to this and many other issues.) Also make sure the lawn received the proper amount of nitrogen during the growing season.
Now, how do we treat this disease. With this type of fungus, there are no spores, so it will not spread as easily as other fungi. You can add some supplemental nitrogen fertilizer to push out new growth and follow proper mowing practices. If you want a faster recovery, I recommend using a contact fungicide. Brands such as Eagle, Strobe, or T-Methyl all work really well. There are many other options that will work as well.
As always, I highly recommend hiring a trained lawn professional to handle these issues in the lawn. They will have to proper equipment and products to handle any issues in your lawn. If you decided to take it on yourself, remember to always read the label of any product you use and apply it at the proper rate. THE LABEL IS THE LAW, and must always be followed word for word. Over applying a product will not lead to better or faster results.
This is a major issue we are seeing currently, especially here in Central Florida. Our weather went from one extreme to the other. We had months without a drop of rain, and now we are getting too much rain too quickly. And the temperatures have been climbing as well. The combination of this results in the disease pictured above. Grey Leaf Spot.
When we get excessive rains causing the grass blades to stay wet for 12 hour straight or longer, and temperatures in the 80s and 90s, it will cause this disease. Symptoms will continue to get worse as the lawn gets more and more wet. But it doesn’t have to just be constant rain for this to occur. If the humidity is over 95% for long periods of time, it will also trigger this disease to rear its ugly head.
Many people will make the mistake of thinking this is just a weak spot in the lawn and try to use a nitrogen fertilizer to push new growth. Never use nitrogen based fertilizer on an area of fungus. This will only ignite the disease and cause it to melt out and magnify the damage.
The best management practice for this is to use a fungicide labeled for control of this disease. Remember, the LABEL IS THE LAW! It is illegal to use any product outside the perimeters of what is stated on provided label. So make sure to read carefully before you use anything, and make sure to apply at the correct rate. Over applying will not solve your issue any better or quicker. That being said, the most effective fungicides for this certain disease are Strobilurin based, such as Heritage, Strobe, or Insignia. Ive tried other types before, but have had the most success using these. I highly recommend that you seek help from a professional lawn company when trying to deal with Grey Leaf Spot. They will have the proper equipment and products to take care of it effectively and efficiently.