Answer: The good news is that Grubex takes 10-14 days to kill the grubs. The bad news is that most of the grubs are very deep in the soil right now and an application of Grubex in March won't reach them. Grubex should be applied in June or July when the grubs are close to the surface and most vulnerable to the chemical. So, plan on a re-application this summer to get the grubs that were hiding deep in the soil this spring.
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