While it is important to know the details of the pest you may be dealing with, most folks simply want to know how to fix the problem. The answer, however, isn’t always cut and dry. The approach that should be taken to control them depends on a few factors; the most important of which is when you actually discover that you have a grub problem.
Let’s say that you discover grubs in your lawn now. Those grubs have been there since late last summer, and are the largest they will be in their life cycle. The best thing to do is apply a preventative application, which will remain in the soil through the time when the new generation of beetles are laying their eggs. Once the tiny new grubs begin to feed on the roots, they absorb the product and are prevented from developing further.
Many people may ask “What about the grubs that are feeding on my lawn now, shouldn’t those be controlled?” The answer to that is: they can be controlled now, but the overall percentage controlled will be low. Beyond that, it’s essentially a lost cause at this stage. Because the grubs have been around and feeding since the previous summer they are large, thus harder to control with the limited curative products that are available. So, unless it is an extremely high-value turf area, curative applications in the spring are not usually recommended as the majority of the damage has already been done.