Peak Period for Grub Damage
'Tis the season...It is that time of year where the annual beetles are starting their flight. Both Japanese beetles and masked chaffers have been seen. Japanese beetles are more of a day time flyer and can be seen on different ornamentals as they feed and cause significant damage to these plants.
The masked chaffers are night time flyers and can be seen around lights in the evening. The peak flight period for the masked chaffers is usually the first week in July. They will lay eggs for several weeks and it requires around two weeks for the eggs to develop and the grubs to emerge. The peak grub damage period usually begins in late July to early August.
There is still time to apply Imidacloprid. This should be put down and watered in to move it past the thatch into the soil. Grubs feed on the organic matter at the soil thatch interface and ingest the Imidacloprid along with the organic matter. Grubs most actively feed when they are in the early instar stages.