“People who cannot distinguish between etymology and entomology bug me in ways I cannot put into words.” (Anonymous)
One of my favorite Dad jokes…”What did the pastor say to the church when he had to bring up the roach issue? Let us spray.
That’s enough of the levity.
In a similar way to weed pressure, pest damage to the home lawn is directly related to weakened turfgrass. Your lawn has natural defenses and abilities to protect itself from damaging pests. Your best assurance of preventing a pest outbreak is to manage irrigation, mowing height, and fertilizer inputs.
Sadly, an industry exists with well-meaning intentions but with more harmful results. No doubt many fertilization and pest control companies want to keep your lawn green and healthy as well as prevent pest problems. However, with improper practices, a healthy lawn and no pest outbreaks are rare occurrences. Every Spring and Fall companies go out and do exactly what you ask them to do: they fertilize your lawn to make it green. The problem happens when this over-realistic expectation of a dark-green lawn is supplied by heavy doses of Nitrogen. Homeowners want the darkest green lawn possible without consideration of the cost to the turf health. When heavy amounts of Nitrogen are applied to a lawn, quick greenup occurs. The problem is that the turf is weakened and insects are attracted to this weakened turf. Exactly how the turf is weakened will be considered later, but for the meantime, remember that dumping uncoated Nitrogen in heavy amounts on your lawn will give you a dark green lawn but can also exasperate pest and disease problems. More on this topic later, but keep in mind your goal should be plant health derived from a realistic expectation and proper fertilization.
There are many pests that can and do attack the Florida lawn. These pests include chinch bugs, grubs, armyworms, sod webworms, hunting billbug, mole crickets, mites, nematodes, etc. it is the author’s intention to create a “simple guide” for a healthy lawn and so I will focus on a few of the more common pests and how to prevent and cure outbreaks.
Southern Chinch Bugs (Blissus Insularis) are the most damaging insect to St Augustine grass in Florida. Areas damaged by Chinch Bugs appear as circular patches of yellowish and brown, dying grass. And there is a direct correlation to drought stressed areas and chinch bug damage. Therefore, it is extremely important that proper scouting happens before a diagnosis of chinch bug damage. Oftentimes a homeowner relies on the knowledge of a landscaper who may or may not have properly scouted for active chinch bugs. And sadly, many will see local dry spots and immediately diagnose that as chinch bug activity. There is simply no reason to treat a lawn with chemicals if it is not needed.
One way to scout for damaging insects in an affected area is to use soap and water. If possible, use a cylinder with both ends open such as a metal coffee can with both ends open. In the area on the edge of the damaged grass, near the healthy turf, drive the coffee can down into the soil by hand as much as possible, preferably 2-3 inches. Make sure you use gloves and push the end that was cut open into the soil to prevent injury to your hands. Then pour in a solution of dish soap like Palmolive and water. You do not need much soap, just a few drops. After a few minutes, once the water goes into the soil, insects should begin to emerge. Refer to the image of the chinch bug below for positive ID.
There are other easy methods to use for scouting chinch bugs. You could simply get down on the affected area closest to a healthy strand of turf and dig around with your hands to see if you can spot any chinch bugs on the blade or in the thatch layer. Another method is to pull up sections of damaged turf that is close to the healthy area and look closely at the stolons. Or simply throw the sections that you pull up at a white surface such as a sidewalk or piece of paper. The insects should be visible. Lastly, a vacuum cleaner or a handheld blower with motor reversed so that insects are sucked up into an attached container is useful.
If you cannot find any evidence of insects then it is possible that something else is wrong. Check irrigation and make sure it is working properly. Or it could be a disease.
If you do happen to find chinch bug activity, it is best to act quickly. Spot treat the area with a combination of contact and systemic pesticide. See appendix for recommendations. And remember that insects can and will develop resistance so make sure you switch up the chemical classes used and do several treatments to ensure that the chinch bug population has been killed.
Another option other than synthetic chemical control is the use of products containing Azadirachtin and neem oil. These are oils derived from trees that exhibit pesticidal properties.
Again, it is important that you take a preventative approach to pest control. If you have historically struggled with pest problems, use a systemic pesticide in early Spring and continue to do so throughout the Summer and Fall. More importantly, don’t over apply fertilizer or use a very slow release Nitrogen source that will only release small amounts of Nitrogen at time. Keep the irrigation system in check and ensure that you are getting the right amount of water on the turf. Remember that sunny areas will need more water than shaded areas. Cut your St Augustine grass at the highest setting if possible.
Grubs are the larvae of many beetle species. In Florida there are many types of grubs, but we will look at the white grub which is the larvae of the Japanese Beetle (Popillia japonica) and the green June Beetle (Cotinis Nitida).
As with any pest treatment, scouting to identify the pest is essential. Turfgrass can naturally defend itself from some grub pressure. So if you are concerned that you may have a grub outbreak, then it may be necessary to pull up some sod pieces and look for evidence. Take a square shovel or sharp knife and cut out a 1×1 square (not always necessary to cut four sides as three sides will be enough to pull the sod piece up). Once you pull up the sod piece, you should see grubs. If there are a few grubs, then you may have another issue other than grubs. If there are many grubs, then you may need to treat the area with a pesticide to knock them back. You can simply place the sod back and water it in.
White Grubs have many natural enemies such as lizards, skunks, moles, armadillos, ibis, spiders, and certain wasps. By planting native flowers, you can attract many beneficial insects which will possibly attract some natural enemies to the grub. Also, resist the need to blanket apply pesticides that kill beneficial insects along with problem insects.
There are some products available that are not harmful to beneficial insects and will adversely affect grubs. One bacterial strain, B. Thuringensis is a bacteria that will kill grubs.
Sod Webworms and Fall Armyworms
Tropical Sod Webworms and Fall Armyworms are major pests for many lawns in Florida. Thankfully, these worms mainly feed on the blade of the turf and not the roots so their damage while sever, may not be permanent. In some cases of severe feeding, the blade may be eaten to the point that it will not recover. In this scenario, with severe damage, the turf area may become infested with weeds.
The main culprit in webworm or armyworm outbreaks is excessive applications of Nitrogen. Increasing top growth of turfgrass can invite a pest outbreak and so it is vital that Nitrogen applications do not exceed the recommended rates (refer to chart in Appendix). The use of high-quality, slow release sources of Nitrogen will greatly curtail the outbreak of pests and still provide enough Nitrogen to keep your lawn healthy.
If you experience an outbreak from either Tropical Sod Webworms or Fall Armyworms, there are many contact and systemic pesticides that are effective. Follow up applications should be made to reduce pesticide resistance.
In addition to systemic pesticides, there are naturally derived pesticides available such as B.Thuringiensis (Dipel) and Spinosad (Conserve).
Spinosad is another alternative to broad spectrum pesticides. Spinosad is a chemical found in another bacteria species, Saccharopolyspora Spinosa, which has properties that have shown success in controlling sod webworm populations.
The Hunting Billbug (Sphenophorus venatus vestitus Chittenden) can cause extensive damage in turfgrass. It is a weevil that is most damaging in Fall or Winter and mainly affects zoysiagrass. Scouting for billbugs is similar to finding grubs. Cut three sides of a square foot section with a sharp knife or square shovel and pull back the sod piece. See if the roots are healthy or chewed up and inspect the soil for grubs. Again, healthy turf can handle some pest pressure but if you have an outbreak and need to apply a pesticide to reduce immediate pressure, then any contact pesticide labeled for billbugs will be sufficient.
Mole crickets can cause some damage to turfgrass, especially Bermuda and zoysia lawns. Typically in the Summer months mole cricket damage is most obvious. Mole cricket nymphs will feed on roots and the tunnelling can dislodge roots so as to cause turfgrass to decline. If you suspect a mole cricket problem (observable tunneling and damage) then take a gallon of water and an ounce of dish soap. Soak a 2×2 area and count how many mole crickets emerge in a 3 minute window. If 3 or less mole crickets emerge then most likely there is no need to apply a pesticide. Many animals feed on mole crickets and can keep the pest pressure down. Furthermore there are wasps (Larra Wasps), flies (Brazillian Red-Eyed Fly), and certain nematodes that prey on mole crickets.
There are several other pests that can and do affect Florida lawns including mites, ground pearls, scale insect, mealy bugs, etc. Resources are available to help identify and treat for these pests in your lawn. Also, each county in Florida has a University of Florida Agricultural Extension office that can answer questions and help diagnose pest issues.
helpful links
https://edis.ifas.ufl.edu/publication/IN383
The Coconut Man Turf and Ornamental, LLC 
Leave a comment