Let's start with the grubs, since most of the problems are
associated with them. We are faced with a few different types of
grubs, with the Japanese beetle larvae and the June bug larvae
being the most common. These also are the grub types most
damaging to your lawn.
Starting with the adult beetles, the
life cycle goes something like this. The beetles mate and lay
eggs in a lush, grassy area. The egg then hatches into a small
grub. The grub overwinters in that stage, diving deeper into the
ground as temperatures cool. In the spring the grub comes back
to the surface as temperatures warm. After a few weeks to a
month, the grub will go into the pupa stage. Then the adult
emerges from the pupa in May or June to start the cycle all over
It normally takes in the range of 10-12 grubs per square foot
to cause damage to decent turf, and with the good growing
conditions we have had this year, that number can almost double.
This means we probably won't see much actual grub damage unless
we have a sudden drought. The other thing is that the grubs will
begin to go deeper in the soil as temperatures cool. Most of the
damage is coming from four-legged critters seeking the grubs as
a food source.
Moles traditionally eat grubs and earthworms. Moles have a
long, straight, shallow tunnel they use and then several short,
curving tunnels branching off where they have sought food.
Skunks will actually dig individual holes to get grubs.
Skunks have a wonderful sense of smell and tend to work in a
specific area. The holes they make are usually about the size of
a penny, and they go as deep as the grub was (usually less than
an inch and a half).
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As for your control options, that gets more difficult this time of
year. A month ago, the best approach would have been to apply a grub
control treatment. But we are approaching the time when the grubs
will go deeper into the ground, so the benefits of a grub control
treatment will be minimal. If the problem is grubs, you are probably
out of luck for this year. Grub controls are best applied in August
or September to control the small ones. If the problem is the
animals eating the grubs, you are going to be reduced to individual
Mole control is best accomplished by trap or poison baits. There
are three main types of traps: the jaw type, the plunger type and
the loop type. The plunger type is probably least effective, since
it is hardest to get set to the proper depth. The folk remedy
controls usually involve bubble gum or Juicy Fruit gum in the runs,
but these don't work consistently enough to recommend them. You're
better off chewing the gum yourself while you are setting the traps.
There are also poison baits available that are effective. The soft
baits, which are meant to imitate grubs or worms, are effective.
Poison peanuts or milo are not, since moles don't eat seeds.
Skunk control is another ballgame. There are state trapping
regulations covering skunks, so you are best to check those out
yourself. There is no season on shooting skunks, if that is an
option where you live. The best control in this case is really your
defense, and that means reducing the grub population where you don't
want the digging occurring. Of course, there may just be a 10-foot
move to another area where grubs are available.
University of Illinois Extension, Logan County]