Rockwall County. A crime is being committed!
Have you seen these criminals? These two are part of a notorious crime family that is sweeping through Rockwall County as we speak. This, my friends, is the infamous Army Worm crime family.
This suspect is the godfather of this crime family. As cute and innocent as this suspect may appear, this mobster’s presence in your neighborhood is an early indicator that your lawn is being cased for a future looting. |
This suspect is one of thousands of soldiers in this crime family. These hooligans are easily spotted as they dress alike and are seen congregating in large groups. They will sweep through your lawn with little notice leaving a wake of destruction behind. |
Joking aside. Army worms are on the march once again. An annual rite of passage through crops, ranges, and neighborhoods across the United States, these worms come through faster than the letter on the door from the HOA about how terrible your lawn looks. Their appetite is fierce. Numbering in the thousands after they emerge, a lawn can be stripped in as little as 24 hours.
The life cycle is simple. Like all butterflies and moths, the moths lay eggs. The eggs hatch. The caterpillar feasts. It makes a cocoon. And emerges as a moth to start the cycle all over again. But here is the bad part……it is a 30-day cycle that can happen two to three times per year. What’s worse is that each year is unpredictable. Some years are bad. Other years we hardly know that they moved through. If you are reading this article, I assume it is a bad year. So how did we get here? Is there something we can do to prevent them?
Let’s start before the war officially begins.
Army worms do not overwinter in North Texas. This important fact is the first part in understanding how “preventing” army worms is not just a simple procedure that you can work into your spring lawn routine. In North Texas, the temperatures are too cold to sustain any eggs or larvae in the soil throughout the winter. Additionally, the adults do not migrate south for the winter like the Monarch Butterfly. Every year, we are greeted by a new generation of moths that grew up in the mild winter temperatures of South Texas. The caterpillars emerge in the spring, start their life foraging on the green vegetation in Mexico and the Rio Grande Valley, and slowly make their way north throughout the summer. Because of this migration process, “prevention” is simply a matter of “observation.” The observation though, is hard to catch early.
Since the army worm moths migrate every summer, one would need to be aware of when the 
first wave of moths begin to make their way into Rockwall County. But the initial migration is nothing in comparison to the onslaught we witness after the second or third generation of worms are wreaking havoc on our lawns. We never really notice the one or two moths that wandered into our yard. We never see the first litter of worms feasting because the damage is so small and limited. And who knows? That first generation may have been hatched at a neighbor’s house down the block. Depending on the year and the location of that first generation, we may not notice the second generation of army worms. BUT WE DO NOTICE THE THIRD GENERATION.
The question is what do we notice first? The numerous ¾ inch moths that are easily disturbed when you walk through the grass or pass by a shrub, or the wave of dead-looking grass that suddenly “appeared” one day as we went to check the mail? Do we notice the numerous ¾ inch moths whose front wings are mottled with light and dark splotches and another spot in the middle of the wing (males), or do we suddenly observe that the lawn appears to be “moving” in the morning or before dusk. Do we see a lot of geckos on the windows at night feeding on the numerous ¾ inch moths attracted to the light inside, or do we notice the large number of birds flocking in the yard feasting like chickens in a coop? If you haven’t figured it out, the “observation” starts with the moths. If you observe the moths, you can then take “preventative” actions before it is too late.
When the moth bombardment flies in, reach for the spreader.
When you are certain that army worm moths have taken residence in your yard, you have a week or so to react. Once the moths lay their eggs, it takes 2-3 weeks for these eggs to hatch and reach their full-grown larval state. It is during this time before the eggs hatch that you can attack before the artillery arrives.
Spread a granular grub-control insecticide containing chlorantraniliprole such as Grub-Ex, or an organic pesticide containing milky spore or Bacillus thuringiensis (Bt). The reason for the emphasis on the chemical chlorantraniliprole or an organic control is that other grub control products leach into the soil and have been proven to play a significant role in reducing earthworm populations. Earthworms are a primary beneficial organism which contribute to the health of your soil. One of the last things you want to do to a damaged lawn is to injure the health of the soil. So, although there are plenty of granular products that kill grubs and army worm larvae, focus on those products that kill caterpillars and not earthworms as collateral damage.
When the army attacks, it’s time to spray
Depending on where you are in your infestation, you are either at the second step in your attack plan, or you are starting to lose the war. Hopefully, you were ahead of the game and managed to spread a granular grub-control insecticide containing chlorantraniliprole before the army started marching across your lawn. If you did, this step may or may not be necessary depending on how many army worms managed to survive your attack.
If you do notice a few foot soldiers or the entire army brigade headed your way, you must ACT FAST. Calling a pest control company will not do you any good at this point in time. Army worms devour the lawn so quickly that by the time a pest control company shows up, the damage is done and the worms have moved down the block.
When you do see army worms or the start of the damage created by them, immediately spray the lawn with an insecticide containing Bacillus thuringiensis (Bt). Bt is a bacterium specifically designed to attack the biological organism of the caterpillar without killing other insects in the process. When Bt has been eaten, the bacteria block the system which protects the pest’s stomach from its own digestive juices. The stomach is penetrated, and the caterpillar dies by poisoning from the stomach contents and the spores themselves.
Or, DO NOTHING and win the war.
Yes. You’ve read that correctly. Do nothing.
If you have a well-established lawn, Bermuda grass and St. Augustine are such aggressive growers that the lawn will recover. Army worms attack the leaves of the plant, not the roots. If it’s about that time to add fertilizer into the lawn, the grass will quickly bounce back after a good feeding. The exception being if you have a new lawn or the grass is already under stress through disease or other pests.
Of course, the HOA will not be thrilled when you tell them, “Don’t fret. Nature will do its job, and the yard will be back to its former self in no time.” Nature will, in fact, do its job. Very rarely do army worms cause such extensive damage that a lawn will not recover. Give your yard a snack and deep drink. You’ll see green within a week or two.
A couple of final notes
Yes, a general pesticide can, and does work. But a general lawn pesticide will also kill everything else in your yard. This includes honeybees, butterflies, ladybugs, earthworms, and other beneficial organisms. These chemicals are indiscriminate in what they kill. They may kill the army worms, but they also leave an extensive amount of collateral damage in its wake. This is one of those situations where too much of a good thing can actually be worse for your yard.
The other side note is that all products that kill army worm caterpillars ALSO kill beneficial caterpillars such as Monarchs, Swallowtails, etc.. Please be careful to focus these treatments to your lawn and not the garden where butterflies may lay their eggs. TARGETED pest management is the key.