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.