According to the product label, "The active ingredient in Criterion 0.5 G Insecticide has sufficient residual activity so that the applications can be made preceding the egg laying activity of the target pests. High levels of control can be achieved when applications are made proceeding or during the egg laying period. The need for an application can be based on historical monitoring of the site, previous records or experiences, current season adult trapping or other methods. Optimum control will be achieved when applications are made prior to egg hatch of the target pest, followed by sufficient irrigation or rainfall to move the active ingredient through the thatch." For the best timing on when to apply this product, we would recommend contacting your local cooperative extension office as they will have information on the best timing for your specific region. In most cases, adult emergence occurs in early summer, often after significant rainfall or irrigation, followed by mating and egg laying. This usually continues for four to six weeks. Under normal circumstances, Criterion 0.5 G Insecticide can provide residual white grub control for four months or longer in turf.