I believe these insects are destroying my overseeded lawn every year. This summer the southern Maryland area was infested with beetles. I just overseeded my yard, what can I use to make sure my fescue won't be destroyed? Is it too late for grub control.(Oct.)
It is too late to apply grub killer, but that's all right because this late in fall the grubs are about full grown, stop feeding, and move deeper into the soil for the winter. In spring they will not feed either. They'll turn into beetles and emerge from the soil, fly away, and mate. Then lay eggs. When little grubs hatch from those eggs and feed next summer and early fall, that's when the damage to your lawn will occur. For those grubs, you may want to apply a grub control product in the spring. (Follow the label instructions for timing.) You should only do that if you have a history of grub problems in your lawn.
However, you may never need grub control. Most lawns never do. True grub problems are the exception, not the rule. Unless you're seeing about 8-12 grubs per square foot , the roots of your grass will grow faster than grubs can eat. Don't use grub control unless your lawn really needs it, because the chemicals will impact the entire biodiversity of your healthy lawn, not just the grubs. A few grubs in the lawn are normal and even healthy.
Tip: Beetles are attracted to moist soil when they are laying their eggs, so don't water your lawn in the summer and encourage them to lay their eggs there.
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