Fall armyworms can cause significant damage to your lawn in a short period of time.
This August, many Maryland property owners have noticed a shocking increase in damage to their tall fescue and Kentucky bluegrass turf. What is causing this sudden collapse? The tropical storm Elsa, which occurred around August 9th, may be a primary factor in bringing the typically Southern fall armyworm up to the Mid-Atlantic region. These tropical storms emanating from the Gulf Coast can carry fungal spores, weed seeds, and insects hundreds of miles in just a few days. Fall armyworms are voracious eaters and can create huge patches of damaged turf. If you are concerned about the presence of fall armyworms, read on to learn more about the appearance, habits, damage, and control of these pests.
Fall Armyworm Appearance and Life Cycle
The larvae of the fall armyworm are initially green and then turn dark olive green with distinctive black dots. When you handle the larvae, they curl into a C-shape and range in size from 1.5 to 2 inches long. Adult armyworms lay their eggs in masses on the grass blades. These eggs hatch in two to three days during hot weather. When the larvae emerge, they move across the turf in large numbers, which is what gives them their name. After two weeks of heavy feeding on turf, they go into pupation and develop into dark grey moths. The entire egg-larva-pupa-adult life cycle can occur in as little as 21 days.
How Fall Armyworms Destroy Your Turf
Armyworms damage your turf during their larval stages. They feed day and night, but most heavily between dusk and early morning hours. The larvae reside in thatch or the upper root-zone, and they feed on the turf leaves and sheaths. They use their pincer mouthparts called mandibles to scrape leaf surfaces and chew on the leaf margins. This creates a tattered and rugged look. When you closely inspect the turf leaves, you can see how the larvae eat with an almost scissor-like precision. Fall armyworms can decimate a lawn or sod field in just a few days.
Signs of Fall Armyworm Damage
The initial injury to your turf caused by fall armyworms will resemble drought stress and damage. Large areas of your turf can collapse rapidly, especially during hot days, and the turf can turn a straw-brown color.
When they hatch, fall armyworms fan out and move through the turf in a radical pattern. This then produces damage that appears as a circular or irregular area of tan or brown turf. Birds are major predators of armyworms and can notice when the turf changes color due to stress. Birds will then begin probing for the insects, leaving numerous small and round openings in the browning or dead surface mat.
What Can You Do About Fall Armyworms?
There are various insecticides you can use to control the fall armyworms that have invaded your turf. It is possible that treatment may be needed to control a second generation this fall. You can discuss with the Scientific Plant Service team what is best for your turf.
Scientific Plant Service Is Your Go-To Source In Landscape Healthcare
Scientific Plant Service, located in Baltimore, is a privately owned corporation, chartered in Maryland in 1957 by Frank J. Burke. We started as a full-service Arborists specializing in the care of shade trees and ornamental shrubs, but today we are a Lawn Care company that is a huge part of the community. From aquatic environments and snow management to deer and mole control, SPS has services tailored specifically for your lawn and landscape.
We offer services in Maryland, Washington, DC, and Virginia, including: Harford, Baltimore, Carroll, Frederick, Howard, Anne Arundel, Montgomery, Prince Georges, Talbot, Queen Anne’s, Calvert counties in MD, as well as Loudoun County, Fairfax County, Arlington, Alexandria, and Falls Church in VA. For more information, contact us online, or call us at 410-321-0970. Be sure to follow us on Facebook, Twitter, LinkedIn, and Pinterest!