Diagnosing summer lawn problems
July is known for hot days with afternoon showers, and so far we haven’t noticed as many showers as expected. We have seen a fair share of dry spots appearing in lawns because of heat stress, and we wanted to address some things to look out for this month to help keep your landscape healthy.
Most of the calls we have been receiving have been related to brown spots in the lawn. The term “brown spot” can be vague, and without seeing the lawn, it can be difficult to diagnose the root cause. Knowing the turf type we’re working with and its recent service history can help point us in the right direction. We also want to rule out environmental factors such as too much shade or standing water. All of our grass types need at least six hours of sun each day to thrive. Clearing overhead limbs and adding sand to low spots can go a long way.
Roughly half of the “brown spot” calls we have received have been related to insufficient watering. In June, we received rainfall after our prolonged drought, and our lawns got used to the additional moisture. It only takes a week or two without rainfall in this heat to begin seeing drought stress. This can be visible in all grass types, causing the grass blades to lose color and wilt.
Other causes of “brown spots” could be mowing, fungal disease or insects, and this is where knowing your grass type comes into play. Bermuda lawns are notorious for showing brown areas the day after mowing. This is because only the top half of the blade has green foliage. If too much of the blade is cut at once, it exposes the brown underside. This is typically not a major concern because it will recover with new growth and can be avoided with more frequent mowing. St. Augustine grass is still experiencing gray leaf spot, a fungal disease that can cause discoloration and wilting. You can identify the fungus by looking for spots on the individual grass blades. Lastly, check for insects any time you see discolored areas. We will cover a few at-home tests in the next section.
If you want to be sure of your diagnosis, there are a few quick tests we recommend the next time you notice a discolored area in your lawn. First, look at the area overall, making sure it is not a defined circle and does not have spots on the blades to help rule out fungus. Next, you can test for insects by pouring a bucket of dish soap and water on the area to bring mole crickets to the surface. You can also hammer a cylinder into the area and fill it halfway with water to bring chinch bugs to the surface. Lastly, if you have ruled out fungus and insects, you can flood the area with a hose. If the problem is drought stress, the grass should begin to recover within a couple of days. If you have a fungal or insect issue, we recommend having it treated immediately.
Insects will continue to be a topic of discussion until late fall. This time of year, we see a high level of insect damage on lawns, trees and shrubs. We have started to see the early signs of sod webworms, which we will discuss next month. Keep an eye out for moths in your lawn at dawn and dusk, as they are often an early sign of an infestation. Whiteflies have also begun to make their presence known in viburnums. We have been seeing higher numbers of whitefly infestations, and it is still early in the season. Look for whiteflies swarming on the undersides of your shrubs to catch them early. We hope everyone has a great rest of the month!
Zach Deloach is the owner of Lawn Doctor of Beaufort County.
