Over last week, our sales team fielded numerous calls of entire lawns fairly rapidly turning brown that others simply diagnosed as drought stress. Upon closer investigation, we discovered that we are in the midst of an armyworm outbreak! This has been occurring all over Ohio and parts of Western Pennsylvania on every type of managed turf from home lawns to golf courses to sports fields. Upon closer inspection, you are likely to find varying colored larvae that are anywhere from 1″ to 1 1/2″ in length at maturity. These larvae feed most readily on lush green turf. Once they have fed off an area, they appear to march in large groups to another food source, hence the name armyworm. Due to the fact that they are nocturnal feeders, we do not always see their larvae. However, you will find a significant amount of frass (technically known as bug poop in the entomology world). Maybe I have that backwards?
Chemical control is available for armyworms, but one application is not always 100% effective. Bifenthrin, lambda cyhalothrin, and Nufarm’s Aloft are a few products that will provide great control for armyworms. The picture below demonstrates the effectiveness of a well-timed application. The green lawn was treated with Talstar 6 weeks ago, well before the outbreak. The residual activity was the only thing that kept this lawn from getting destroyed! During most years, parasitic enemies keep armyworm populations down to a controllable number. However, a cold, wet spring, like the one we just experienced, reduces the effectiveness of these parasites, allowing large populations of armyworms to develop.
The old adage to not judge a book by its cover fits well here. Look beyond the initial symptoms shown by turf and dig beyond the canopy into the root cause of the problem. As always, contact your local Advanced Turf rep for advice and recommendations!
