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

The recommended months for controlling white grubs, particularly those associated with Japanese beetles, focus on periods when the larvae are actively feeding and are most vulnerable to control measures. May and June are particularly significant as this is when the young grubs hatch from eggs laid by adult beetles and begin to feed on the roots of grass. Applying control measures during this time can significantly impact their population.

The option of August and September is also crucial because these months correspond to later developmental stages of the grubs. In late summer, grubs are still present in the soil, and many control methods can effectively target them before they enter the colder months and become less active.

In contrast, the other months listed in the options do not align well with the active life stages of white grubs. February and March are too early, as grubs are typically dormant in the cooler temperatures, while April and May can be too early for effective treatment, as the larvae may not have hatched yet or be in their earliest feeding stages.

Thus, the answer is prudent because it captures the critical timing for intervention when grubs are feeding and susceptible to management practices.