Fall Army Worms

Our entire area is seeing a Fall Army Worm Invasion. These “worms” are the larvae (caterpillar) stage of the Fall Army Worm Moth. They have taken Virginia by storm and surprise. The FAW does not normally come up this far north. It is thought that tropical storms and hurricane winds brought the moths this far north. Virginia Tech Entomology professor, Dr. Thomas Kuhar is quoted in Bloomberg saying this is “the largest infestation I have seen in 30 years.” Dr. Kuhar posted an article on Virginia Cooperative Extension saying that “this outbreak could lead to one of the heaviest pest problems that we have experienced in Virginia. Lawns have completely been destroyed by these voracious feeders.”

What you need to know:

• Fall Army Worms eat day and night and can destroy your lawn in one day. A football field can be consumed in less than 3 days.
• Please inspect your lawn carefully for these caterpillars as soon as possible.
• The earlier you find them the easier they are to kill. Once the larvae are longer than 3/4”, they become difficult to treat and have already done a great deal of damage.
• If you find them or any signs of damage, act as soon as possible to try and save your lawn.
• FAW will eat your grass, leaving brown, dead grass behind. It may look like drought or fungus damage. It happens very quickly.
• By the time you notice the damage the FAW may have finished eating and starting to burrow into the soil to pupate. Then the entire cycle begins again.
• The FAW arrived in our area, migrating from the deep south. Our warm climate, high rainfall, and humid nights create a favorable environment for the eggs and larvae to survive in large numbers.
• These pests will be in our area until the first hard frost in October. They cannot live in freezing temperatures. Continue to inspect your lawn until that time.
• You may not have been a victim of the pest yet, but they will be here for the next 2 months. There is a good chance you will get them.
• If you have already had FAW’s, you can still get them again. The life cycle of this moth allows for multiple generations to be born this season.

The life cycle of the FAW is:

1. A moth flies onto your property and lays her eggs. She lays 100 – 200 per cluster and 1,500 in her two weeks of life.
2. The eggs hatch within 3 – 7 days.
3. Fall Army Worm larvae start to feed and grow over the next 14 – 21 days.
4. FAW finishes eating and burrows underground to pupate.
5. The caterpillar spins a cocoon and stays underground for 7 – 14 days.
6. The adult moth emerges.
7. The moths mate and the cycle continues.
8. Adults live 10 – 14 days.

What to look for:

• Your lawn looks nice and green and then overnight you see brown areas. A day later, half of your lawn is brown and dead. You probably have Fall Army Worms.
• Fall Army Worms get their name because they travel together and march across a lawn like an army, eating as they go and destroying everything in their path.
• The adult moth is 1½” and is gray with brown and white.
• The eggs are laid in masses and are covered by gray or white scales that give them a fuzzy appearance. They darken as time goes on to black before hatching. Destroy them if you find them.
• The eggs can be anywhere – on plants, decking, siding, fences, trees, grass, etc.
• Check your lawn regularly. The larvae are very small at first and do not do very much damage. It is hard to find them at this stage.
• The larvae eat in the early morning, late evening, and nighttime. During the hot daytime, they are near the ground, shaded by the grass.
• The larvae eat above the ground, not the roots. They start at the top and move down eating the green leaf tissue and leaving brown grass behind.
• You may see brown, ragged tips early on.
• The larvae change and grow over time. It begins light-colored with a dark head. They become darker green, brown, or black with three light stripes and dark spots.
• The larvae grow to about 1½” – 2”.
• The telltale sign is an inverted Y-shaped suture on the head between the eyes.
• If your lawn has brown areas, search them for larvae.
• You can also try a soap flush. Take a 5-gallon bucket. Add a tablespoon or 2 of dish liquid and fill with water. Pour the solution over a 2-foot square area. If you have FAW, they should move to the top of the grass in a few minutes.
• If you see more birds than normal feeding on your lawn, that may indicate FAW.
• If your neighbors have FAW, you may get them soon.

What to do now:

• FAW causes a rapid loss of leaf tissue in turfgrass.
• If left unmanaged, they will cause considerable damage.
• If you discover you have FAW, you must act quickly and treat your lawn.
• We will be happy to advise you on a treatment plan. We can treat your lawn for you or give you information to treat your lawn yourself.
• There are many insecticides to treat your lawn depending on the size and age of the infestations.
• However, there are no true preventative treatments to ensure you do not get FAW.
• If possible, mow your lawn before treatment.
• Tall Fescue lawns do not usually recover well from a Fall Army Worm invasion.
• Lawns normally need to be over-seeded. Fertilizer will also help the lawn recover.
• You may want to consider core-aeration if your lawn has significant damage.
• The key is to monitor and be vigilant, watching for signs of trouble so you can catch and treat this pest early.
• Please contact us with questions or for advice or any services you may need.