Both species complete one generation per year. Adult males are attracted to lights at night, mostly from mid-June through July. All turfgrass species are susceptible to masked chafer damage. Damage is usually more serious on ryegrass and bluegrass turfgrasses, whereas fescues are somewhat less affected. Warm season grasses tend to be the most tolerant of grub feeding.
Symptoms resemble drought stress and exist even where there is sufficient irrigation.
The most damage usually takes place in late summer or early fall. Digging by vertebrate predators, such as crows, raccoons, skunks, and coyotes, is a common indication of high grub populations. Tiphiid wasps are common parasites of masked chafers, but may not consistently be effective in reducing grub populations below damage thresholds. Establishing warm season grasses may reduce white grub damage. Thorough spike-aeration of turf also kills significant portions of white grub populations when they are feeding close to the soil surface.