Army Worm - Pain in the Grass Wasp Eating Army Worm - Bite Marks on Leaves Controls Mosquitoes and Army Worms
By Bill Lamson-Scribner
Horticulture Hotline 10/03/26
Some situations keep coming back year after year. A few
topics that I wish I could take a few years off from writing about are moles, army
worms, sod webworms, mosquitoes, large patch fungus, gray leaf spot, chinch
bugs, nutrient deficiencies, weeds, heat, drought, vines, fire ants, lace bugs,
rats, flies, fleas, termites and roaches; however, these topics seem to be
dominating the question counters at the three Possum’s year after year.
One great thing I experienced this week was my favorite
fragrance in the landscape – the sweet tea olive. Not only a great fragrance
but for me it usually means cooler weather has arrived!
On a not-so-great note the cloudy weather we recently had
gave great cover for the army worms to appear. We have had reports from all
over the Lowcountry and even the beloved Possum’s North was attacked. Not too
smart – dead army worms now!
Army worms will affect the aesthetic value of the green
grass on athletic fields, golf courses, and home lawns, and the worms thin the
canopy of the grass. They can cause economic damage in hay fields, corn fields,
and other crops. Prostrate growing weeds like spurge, doveweed, lespedeza and Virginia
Buttonweed seem to come in the fastest on home lawns..
The army worm adult moth can lay over 1000 eggs. She usually
lays them in groups of 50 to several 100. The eggs hatch in 2 to 10 days. The
larva then eats your grass for 14 to 21 days before they return to the soil and
pupate. New egg laying moths emerge in 10 – 14 days. With several hundred
larvae eating your grass at once, you can imagine how quick army worms can ruin
your grass.
What bothers me the most is you work all summer on your
grass to have it look nice, and once the grass starts to slow down for the
winter, fall army worms and then sod webworms attack the grass. Look for areas
that appeared to have been mowed low and with a dull blade. You can see that
the leaf blades have been chewed. Also thatch type debris will be churned up on
the surface. Birds and low flying wasps are also predators of army worms, so they
can be an indicator that you are under attack.
Since army worms are in direct contact with the ground, they
are very easy to control. Bug Blaster, Bifen, Mosquito Pro, Cyonara and
Acephate will all put a hurting on army worms. Thuricide (Bt), EcoVia EC and
Spinosad are organic products that will also work well if you get them while
the worms are small. Since the population of worms is so high and hit so hard,
keep your eye out for a second hatching.
Watch for moths in your yard around dusk. If you begin to
see a moth that gets out of the grass, flies for 6-10 feet then lands again
(like a bobwhite quail for you bird hunters) you may want to consider using one
of the above-mentioned products.
We just had a wind event that came up from the south. The moths
of these worms will often catch rides on wind currents from areas that they are
active year-round. Watering first to bring the worms to the surface and
applying products in the evening when the larvae are about to feed, will often
help your success depending on the product.
Now is the time to put out preemerge products in the lawn
and beds to prevent those small seeded annual weeds. Henbit, chickweed, Poa
annua (annual bluegrass), cudweed and lawn burweed are a few of the winter
weeds that would like to occupy your lawn and flower beds. Poa annua (the green
grass that is very visible in February and March) and lawn burweed (the
prostrate growing weed that develops a sticker) are usually the most hated of
the winter weeds. Some people use profanity while describing them at the
counter of Possum’s!
With all the recent rain fall, cooler temperatures, and
shorter daylight hours large patch fungus is becoming a big issue. Use fungicides
preventively to save money and aggravation. Now is also a good time to identify
any drainage issues.
The “nasty rascal the chinch bug” is still sucking the life
out of many lawns. Gray leaf spot is still alive and doing well. With the rain,
fire ants are mounding up everywhere – be careful where you step! With the high
tides and rains mosquitoes are out and biting, especially in the evening. Rat
trap and roach control products are exploding at Possums – they want to get out
of the cool weather and rain too!
Always read, understand and follow product label. The
product label is Federal Law.

