Grub season traditionally begins August 1 in most of the northern United States. The Japanese beetle and masked chafer adults have laid the majority of their eggs, which will begin to hatch shortly. Preventive applications of insecticides are the most effective means for controlling grubs. In areas where grubs are a chronic problem, treatments should be made. Treating preventively is based on the premise that grubs are easier to control when they are small and actively feeding than when they become more mature (large).

During early- to mid-July, Japanese beetle adults are obvious to many superintendents mainly because they are feeding on ornamental plants or landing on putting greens. However, in some cases the Japanese beetle is absent.  Don't confuse this with the thought that grubs will not be a problem.  The masked chafer often goes unnoticed because the adult appears at night.