PEST MANAGEMENT
Fall armyworm damage to a tall fescue field without the endophyte ( right ) and a tall fescue field with endophyte ( left ). Photo by Dr . Kevin Mathias .
Symptoms will include an irregular pattern of dead turf very close to healthy turf . The adult chinch bugs are very small (~ 1 / 6 ” long ) and have a gray-black body , white wings , and reddish legs . Nymphs ( juveniles ) are smaller than adults and are orange to red with white bands across their back . Wing “ pads ” are present on the fourth and fifth instar nymphs . Monitoring for chinch bugs can be accomplished via soap flush — mix 3-5 oz . of dish soap in 3-5 gallons of water and gently pour this mixture onto the area where you suspect activity . Saturate the soil and wait a few minutes to observe insects floating to the surface . The soapy water will irritate them to emerge from the soil and then a count can be conducted . Research suggests that 15 to 25 chinch bugs per square foot may warrant control when chinch bugs are actively feeding in the summer .
Chinch bug damage is usually less noticeable in spring and early summer ( the most noticeable damage usually occurs in late summer / early fall ). Hairy chinch bugs have two generations per year in most locations . After adults emerge from overwintering in spring , they mate , and the adult females lay eggs in early summer . Second generation adults lay eggs from mid-July to late August and the second-generation nymphs ( juveniles ) develop in the fall .
BILLBUGS There are several billbug species , but the bluegrass billbug and hunting billbug are the most common in turfgrasses . Damage symptoms resemble drought and can occur from late June to early August , so sometimes the damage goes unnoticed in dry conditions since it is difficult to distinguish from drought . The life stages that cause the most damage are the first two larval instar stages . Females lay eggs inside the turfgrass stem . When the eggs hatch , the first two larval instars tunnel through the stem and then feed on the crown of the plant and roots . Since the adults crawl along the ground , pitfall traps can be used to monitor activity . One important indicator of damage from early instar larvae is the presence of frass , created as the billbugs chew on and then excrete leaf stems .
Another way of identifying billbug damage is the “ tug test .” If the turf leaves tug away easily and frass is present , this is a strong indication of billbug feeding . ( Conversely , grub feeding will keep the lower stem and crown in place , but the turf will have very few roots .) Endophyteenhanced grasses can be used to deter billbug feeding . Manage thatch to appropriate levels . Be sure to adhere to appropriate fertilizer and irrigation practices . In fields that have had high billbug pressure in the past , spring applications of contact or systemic insecticides can be made based on monitoring with pitfall traps and growing degree day models . Preventative applications are targeted at adults in May prior to egg lay .
SOD WEBWORMS AND CUTWORMS Sod webworm larvae are tan / gray with small dark spots and brown heads , and reach ¾ ” to 1 ” fully grown . After overwintering as late instar larvae , the adults emerge as tan moths . Female moths of sod webworms fly just above the ground surface in spring in a zigzag pattern , laying eggs as they fly . The eggs land in the turf and
30 SportsField Management | September 2023 sportsfieldmanagementonline . com