In turf management, insecticide applications for sod webworm larvae are considered when how many webworms per square foot are detected?

• A. One to two webworms per square foot
• B. Two to four webworms per square foot
• C. Five to six webworms per square foot
• D. Seven to eight webworms per square foot

Answer: (B)

The concept being tested is using an action threshold to decide when to apply insecticide based on pest density. For sod webworm larvae in turf, the recommended threshold is two to four larvae per square foot. This range balances the risk of economic damage from feeding with the goal of avoiding unnecessary sprays. At densities below two per square foot, turf can usually withstand the activity and natural controls may keep the population in check. Once you detect two to four larvae per square foot, the potential for noticeable damage increases, and treating at that point helps prevent larger losses and can be more cost-effective than waiting for obvious symptoms. To apply this, scout representative one-square-foot areas across the turf, count the larvae, and base the decision on the average density. If you consistently find fewer than two, monitor; if you find more than four, plan an insecticide treatment.