Fall Armyworms! The other insect that will kill your bermudagrass

The Fall armyworm starts to invade your bermudagrass lawn in August or September.  You will never see them.  You’ll just see weak or bare areas of your lawn and think it’s drought-related.  Fall armyworms can eat during the day but to see them you must usually dig into the thatch or soil layer since they are not too active during the day.  It’s much easier to see them at night when they come out of hiding to feed on your grass more actively.  They eat all the above-ground bermudagrass, unlike grubs that eat the below-ground roots.

If you want to see them during the day without digging just put a glob of baby shampoo or dish soap on your lawn and spray with a hose until the surrounding grass starts to flood with water.  You will see the worms float to the top.

They are the larvae form of the adult Fall armyworm moth.  The moths go into your grass and lay eggs on the underside of your Bermudagrass blades.  One female can lay up to 1,500 eggs. If you walk through your grass and see these moths fly out every now and then, that means they are laying eggs in your lawn and you will see Fall armyworm larva that will eat your lawn within a matter of days. Another indication is when you see crows fly onto your lawn and begin tearing and pecking at your grass trying to eat the larvae worms.

They lay their eggs in 30-day cycles which overlap so sometimes you’ll see big mature Fall armyworms and baby ones at the same time.

The larvae go through about 6 stages where they change in appearance. The mature Fall Armyworm larvae are very easy to identify by their markings and come in different varieties in Texas with a few different color shades:

Fall army warm damage will look like this because they tend to march from one area to the next eating away. Big swaths of grass in bad infestations.  You can put down all the fertilizer and water you need and your grass will look great in some areas but then you’ll see areas like this that don’t seem to get any better. If you only manage to spot 1 or 2 Fall armyworms, this will mean you likely have an infestation of them that you are not seeing.

If you use the Duocide insecticide treatment I specified in the schedule it will kill the Fall Armyworms due to the Carbaryl and Bifenthrin.  Be on the lookout around August and September just in case you see damage like the above start to form and you need to put down an extra-light treatment.

There are also sod webworms and cutworms which are also similar to Fall armyworms and can cause severe damage to your Bermudagrass lawn as well.  Some years in Texas the sod webworms are a bigger pest for Bermudagrass than the Fall armyworms are.

Sod webworm moths are usually smaller white-colored moths fluttering around in your lawn. Walk your lawn or spray into it using a hose and you may see them fly out which means they are in there laying eggs and you will see webworm larvae soon.

Don’t use color and size alone to ID your worms.  Look for the markings I specified.  Even then at first glance these worms seem similar so take a bunch of pictures on your phone zoomed in and then compare to the images above.  There are 20+ types of cutworms for example. 

Don’t worry, you don’t have to become a worm expert. All of these pests can be controlled with the Duocide insecticide treatment as well. As soon as you see moths fluttering around in your grass, you know you will see worms that will damage your grass soon. Just put it down on the date specified in the schedule and you will be fine.