Soil Feeders - Northern Masked Chafer (NMC)
Southern Masked Chafer (SMC)

NORTHERN MASKED CHAFER (NMC)
SOUTHERN MASKED CHAFER (SMC)
scientific name: Cyclocephala spp.

FIELD KEYS
Hosts: Most grass species
Site symptoms: Turf wilting under heat stress despite adequate available moisture. Turf is unresponsive to water and fertilizer applications. Wilted turf turns off color and dies in irregular patches to large uniform areas. Removed dead or wilted turf reveals grubs feeding at soil-thatch interface down to 2-inch soil depth.
Plant symptoms: Above-ground plant structure shows no obvious damage or other symptoms. Root system shows extensive damage from the crown down to a 2-inch depth.
Site keys: Sunny locations with consistent soil moisture and higher organic content.

SPECIMEN ID
Immatures are typical six-legged white grubs with tan heads that range in size from 1/8 inch for newly hatched first instars to 1 inch fully grown third instars. Adults are 3/8 to 1/2 inch-long yellow brown beetles with darker brown heads.

SCOUTING TIPS
Masked chafers have typical one year life cycles. Adult NMC flights begin when degree-day accumulations reach ~ 900 (base 50°F) and SMC flights begin when degree-days reach ~ 1000. Monitor adult numbers with light traps. Sample about three weeks after adult numbers peak. Over-wintering 3rd instar grubs begin feeding when soils thaw or warm. Sample vulnerable sites with a recent history of masked chafers infestations in the spring.

CONTROL STRATEGIES
Cultural: NMC and SMC eggs are particularly susceptible to desiccation in drier soils, so where possible limit supplemental watering at vulnerable sites (to increase egg and first instar mortality) starting when adult flights peak. Increase drainage at wet sites and manage turf for maximum root production.
Chemical: 3rd instar masked chafer grubs often spend as much time feeding on dead organic matter as they do on grass roots. Damage threshold population densities can vary depending on turf vigor and moisture. Where no damage is visible, consider applications to asymptomatic when grub population samples are over 10 per square foot. At more vulnerable or low maintenance sites, applications may need to begin once grubs populations reach 6-8 per square foot.


Growth stages: egg - grub (three instars)* - pupa - adult
* - treatable stages

Life cycle: 1 year life cycle
Sequence: grub - pupa - adult - egg - grub