They are short lived as adults, and the adult beetles do not damage the turf. After mating, the female lays eggs on the turf which then develop into small grubs. The grubs feed on the roots during the summer and then in the fall go deeper into the soil staying there through the winter. They feed to a lesser degree the next spring and turn into adults usually by early June. The best time to control the grubs is during mid-July, when the grubs are small, have sensitive skin and are close to the surface.
Damaged turf is off color, being light green, yellow and thinned out.
Severely damaged turf can be pulled back in small patches. When ingested by the grub, this product causes the grub to stop feeding. This is catastrophic for a young grub when applied in July to early August. Bt is active against Japanese beetle larvae, but to the best of my knowledge, it's not active on the other grubs we have in Arizona. Arizona Board of Regents.