What months are recommended for controlling "White grubs" (Japanese beetle)?

Controlling white grubs, particularly those associated with Japanese beetles, is most effective during the months of May, June, or August and September. During these times, the lifecycle of the beetles facilitates effective intervention.

In late spring (May and June), white grubs are in their larvae stage and are actively feeding on grassroots. This is an ideal time for treatment, as applications made during this window can significantly reduce their populations and subsequent damage to turfgrass. By addressing the issue proactively when the larvae are vulnerable and feeding, turf managers can ensure healthier grass and prevent issues later in the season.

In late summer and early fall (August and September), it's important to continue monitoring and managing these pests. This period often marks the peak of grub activity as they prepare to pupate before the colder months. Treatments during this time can help control those that may have survived earlier interventions or are newly hatching.

The other choices fall outside of these optimal periods. Early spring treatments in February and March may not be effective since the larvae are either not yet active or are too young to be targeted effectively. Likewise, the months of April and May may not fully capture the peak emergence of grubs that occurs later in the season.