How to Do It Yourself for the Greenest Bermudagrass on Your Street!
Grubs and beetles. The never-ending cycle of death for your lawn. You see beetles around May or June time all over the place but where do they come from? They come from your lawn. When the adult beetles are still larvae (babies) they are called white grubs and eat your lawn’s roots causing your grass to go brown and die. Your goal is to break the cycle. The white grubs under your lawn all look almost the same with their white bodies and copper heads but depending on your area, these white grubs may be from one or more of the following types of beetles. There are over 30,000 types of scarab beetles around the world but these are the ones that are found in the US most commonly:
Some of the grub larvae from these beetle families are resilient to certain grub killers. Some grub insecticides can only be put down during a narrow window of time to control and kill them so please read and understand what your best options are below before taking action. The types of beetles that most commonly affect Bermuda grass are May/June Beetles which has just one large generation every year. Other grass types can be impacted by multiple generations every year such as with the Black Turfgrass Atanenius Beetle.
If you do dig under your lawn and spot white grubs, they all look very similar with their fat white bodies and copper/brown colored heads but there are a few distinguishing features if you wish to identify them. The grubs can be 3/8″ to 2″ in length (1 cm- 5 cm) and have 3 legs on either side of their heads. If you look at the tail section of the white grub, there is a section called the “raster” which has a unique pattern to each beetle family. This raster pattern is just a section of short hairs and spines on the underside of the white grubs’ abdomen. Don’t’ worry you can pick up the white grubs by hand if you want to inspect them, they don’t bite:
Here is a zoomed in view of the white grub raster patterns if you are more interested.
As the beetle’s egg hatches, it will go through 3 larval stages called instars. You must choose an insecticide that can kill in the 1st instar, 2nd instar, and 3rd instar stages. Some may not be effective in the 2nd and 3rd instars since the grubs are so hardy but there are several that will work and are recommended further below. After that they turn into pupa and finally the adult beetle will emerge in May and June beginning the life cycle over again with a new batch of eggs.
Irregular brown dead grass spots like this:
These white grubs live under your grass and eat away at the roots of your grass. This causes large brown areas in your grass and you think it’s because you are not watering enough or have some kind of grass fungal disease. They are the hidden killer of Bermuda grass. Want to confirm if the problem in your lawn is grubs?
You will have grubs every year. Some years the damage can be overcome by new grass growth so you won’t even notice the grub damage for too long. Other years due to drought and not enough watering, not enough fertilizer, other insects damaging grass, etc. your grass can’t overcome these compounded problems and just dies out. That is when you the homeowner usually panics.
If you follow the treatment specified in the Bermuda Grass Monthly Maintenance Schedule it will break the grub life cycle saving your Bermuda grass. June, July, and September are the most critical for grub prevention and grub killing because there is a good overlap of mature grubs and new hatchlings. Click on the image below for a zoomed-in view and look closely at the grub life cycle showing where they are in your lawn throughout the year.
Notice how close the grubs are to the surface eating your grass’s roots twice a year. During March, April, May as they fatten up before becoming beetles and again during the July, August, September, October months when the new batch of larvae are just born. These are the times when you will notice your grass starts to die from the damage the grubs are doing. These are also the times when you can actually hit the grubs with an insecticide that will reach them which means effective killing and breaking the grub life cycle. In a nutshell, if your grub preventative you put down in June kills the majority of the hatchlings then in September you only need to put down a small dose of grub curative (grub killer) to kill the remainder. This reduces damage to great sections of grass making it more resilient to grub damage and able to grow through any damage a small number of grubs may be doing. Keep doing this every year and it breaks their lifecycle which means no damage to your grass!
Sometimes if it is the time of the year that the grubs are close to the surface you may see crows fly onto your lawn and begin tearing up and pecking at your grass eating these nice juicy grubs. This is a big indication you have a grub problem and will have grass damage happen very soon.
There are many animals that love to eat grubs like raccoons, wild boars/feral hogs, skunks, armadillos, moles, and more. They are foragers and will tear up your lawn in the middle of the night, you will wake up to your lawn looking like this:
Grubs live under the soil and never come up until they are beetles. Many of the products that are advertised as grub killers do not contain any chemicals that can penetrate down into the soil. They will just bind up to the organic layer of your grass and thatch which means they will only kill surface insects. Sure they can kill grubs, but only if you dig up your lawn and apply it directly to the grub! It’s false advertising. Spectracide Triazicide Insect Killer for Lawns is one of the biggest offenders of this false advertising with a big white grub right on front of their package:
Be educated, don’t fall for this. The product is cheap and promises everything under the sun, however, it does not contain the chemicals needed to kill grubs deep in your soil. I will never buy another Spectracide product because of this marketing practice. Products you find in the pesticide and insecticide sections of Home Depot or Lowes that contain only the following active ingredients listed on the front of the bag are useless against white grubs and WILL NOT WORK:
There are only 2 known insecticide chemical compounds that will kill white grubs:
It is very hard to find pesticides at Home Depot or Lowes that will contain these compounds. Manufacturers of pesticides in the big box stores must target the most amount of bugs and still keep the costs of their product down so you actually buy them. For that reason, the additional expense of adding one of these chemical compounds to their formula is cost prohibitive for them. Your only option is to purchase from Amazon. These are excellent products I have used:
There also used to be a product called Sevin Lawn Insecticide Granules which used to contain Carbaryl. It has been reformulated with Zeta-Cypermethrin and Bifenthrin as the active ingredients several years ago so will no longer kill grubs.
You can put down pesticide products that contains Carbaryl or Trichlorfon at any time of the year to kill white grubs. Usually it will be in July, August, September when grubs are damaging your lawn the most and you need to put it down.
There are only 4 known insecticide chemical compounds that will prevent white grubs from becoming a problem in your lawn and can only be applied in June to be effective. Some are more effective than others and will reduce the grub population under your lawn significantly which means less damage to your lawn:
You can only use these products in the month specified! They are ineffective at any other time of the year and you are wasting your money by putting down the product. They only work on newly hatched grubs in the initial larvae stage ready to eat which is usually July, a very narrow window of opportunity. They are systemic pesticides which means they are for the grass. The grass sucks up the chemical and when the initial stage white grubs eat the grass roots, they get a dose of the chemical. This is why you must get the chemical put down well ahead so it works down into the soil and gets absorbed into the plant ready for the grub to take a bite when it hatches. Some of these chemicals can kill the grubs but sometimes they don’t get enough of a lethal dosage. In that case, some of these chemicals act as appetite suppressants which means the grubs think they are full after a few bites and then don’t eat anymore. They starve themselves to death!
These are excellent products I have used that contain these chemicals. Just remember to only apply them in June or July so you don’t waste your money putting down the product when it will be ineffective for grub control:
Unless you are a crow, raccoon, wild boar, armadillo, etc. and like to dig and eat grubs, there are not many alternatives to using insecticide to kill grubs. Many insecticides also kill beneficial insects such as honey bees, earthworms, ladybugs, etc. There are a few organic remedies for grubs but some may not apply to you.
If you are 100% sure you have only Japanese Beetles in your area and those are the grubs in your lawn, then you can try one of these. If you have multiple species of beetles in your area, then you will have multiple types of grubs in your lawn so these won’t help you as well as an insecticide would:
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