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Expert Tip Monday: Ew! Fall Armyworms Infest Atlanta!
Worm Alert! This may be one of the worst-ever "Fall Armyworm" Seasons Atlanta has ever seen. Our friends at SuperSod.com are here today to educate us a little on what Fall Armyworms are...and how to get rid of them. The health of your lawn could depend on you reading this blog post!
Fall armyworms (aka "FAW") are a threat to lawns right now and will continue to be a threat until first frost.
Across the Southeast, our Super-Sod store managers are reporting that this is probably the worst season for fall armyworms that they’ve ever seen. This includes our Atlanta stores and that’s why we are working with Atlanta Home Improvement Magazine to get the word out with an “alert” and with facts to arm folks with lawns. Consider yourself “alerted” and please read further to educate yourself about this voracious insect.
If you don’t use the information yourself (and I hope you don’t have to), you may be able to help a nieghbor or friend with your knowledge. When you see a sign of them, treat your lawn immediately because they can do terrible damage within 24 hours. Treatment time should be late in the evening or early in the morning; both times are when they are most active. Liquid insecticides are best and we recommend two treatments: one in the evening and one the next morning.
FAW Entomology Lesson, in Brief
Lifecycle of fall armyworms: eggs > larvae > pupae > moths
FAW eggs are laid in shrubs adjacent to turf or in surprising, non-leafy places like sides of building, fences, posts, signs, old cars, and I've even seen a picture of their egg masses on a flag. We rarely see them in our production fields because with hundreds of acres of tightly mowed turf there is nowhere suitable for them to lay their eggs.
The larvae (singular is larva) emerge from the hatched eggs and it’s the larvae that will feast on your lawn. The “larvae” are really the "worms" which are really "caterpillars." FAW are not really worms at all, it's just a catchy name. (remember: earthworms are GOOD for your soil!)
The lavae metamorphose into pupae (singular is pupa), which are non-damaging, but they are hideous, cockroach-colored, torpedo-shaped awful things that bury themselves into the soil so we don't have to see them, thankfully.
The pupae metamorphose into moths, which are considered the adults and, as such, produce offspring. The moths lay a new round of eggs and the cycle repeats itself.
Lesson from the lifecycle of FAW: if you've had fall armyworms once, look for them twice. We hate it too.
What to Look for and How to Kill FAW
Increased bird activity is a sign of FAW presence in your lawn because the larvae are a tasty meal for birds. Also, your lawn may suddenly appear brown and look like it’s been exposed to frost. If you see either of these signs, we recommend testing for FAW with a soap flush.
Soap Flush Method for Diagnosis in the Larval Stage: Mix 3 tablespoons of liquid dish soap with 1 gallon of water. We find that lemon-scented dish soap is the most effective. Pour the mixture into a 3 foot by 3 foot area and watch the activity that results. The soap will agitate the caterpillars' skin and they will come to the surface - you can see them and then you will know to treat for them immediately.
The larvae/caterpillars are the damaging part of the life-cycle. Notice how you don't see them everywhere at once on your lawn. They march from one side of the lawn to another and this shows that they hatch from eggs that were deposited adjacent to the lawn. If the FAW came with the sod, they would be everywhere at once eating sod. (Read more about this under “New Sod” below.)
We're written a lot about FAW in our July Lawn Tips email and strongly recommend that you follow that link to read even more about FAW, but there are two points I'm going to pull from there:
#1. There is no "over the counter" preventative treatment available to homeowners for FAW in the egg, pupa, or moth stages. However, insecticide is available to homeowners for treating when they're in the larva/caterpillar stage, which is when they are doing their damage.
#2. When you see a sign of them, treat your lawn immediately because they can do terrible damage within 24 hours. Treatment time should be late in the evening or early in the morning; both times are when they are most active. Liquid insecticides are best and we recommend two treatments: one in the evening and one the next morning.
A Special Note About FAW’s Love of New Sod
FAW love new sod above anything else, but they will eat established sod too. Their culinary propensity for new sod makes it appear that they arrived WITH new sod, but lawn care experts and extension specialists are familiar with this problem and know that FAW are already on site before new sod is laid. New sod is like a fresh buffet spread out before them.
Further Lawn Care after FAW are Killed and What to Expect
After you've applied your insecticide treatments, apply a starter fertilizer (5-10-5) to your lawn the next day. Continue to water your lawn each morning for several days.
In most cases a warm season lawn (Bermuda, Zoysia) will recover. FAW don't eat the stolons and rhizomes of warm season turf and growth will resume from these resilient plant parts.
Warm season lawns (even brand new ones), given proper care, will typically recover from FAW damage, but damage to new tall fescue is often disastrous. Tall fescue simply does not have the same tolerance to FAW activity, particularly if the lawn is not very well established. As a result, FAW damage in tall fescue often requires overseeding or re-sodding in order to repair the damage.
Homeowners with lawns, please do not take the FAW threat too lightly. Any lawn can go from fine one day, to a complete loss in a little as 24 to 48 hours. Please call us at Super-Sod if you need further advice.