Grubs Are Coming To Your Lawn!
Next month, from about July 15th to the 25th is egg laying time for
grubs in Northern Illinois. Egg hatch will follow about two weeks later.
The grub population and damage appearing in August depends on the number
of adults present to lay eggs and on favorable soil conditions in sod
areas. Adult grubs, which prefer moist soil, lay most of their eggs
between 9:30 p.m. and 1 a.m., with a peak period at about 10:30 p.m.
Female beetles bury the eggs beneath the soil surface. They prefer open
lawn areas but usually deposit more eggs along sidewalks and driveways.
The soil in these areas may be wetter, and the concrete or asphalt is
probably still warm at night from the day's sun.
If you want to scout for annual white grub activity, walk along some
streets in your community after 10pm and observe the grubs' egg laying
activity in the oncoming car lights. The wings of the adult beetles
will be long and filamentous. There may be as many as 10 or more per
square foot flying slowly just above the sod and dropping down into
the grass to lay eggs. This activity can also be observed on the fairways
of golf courses and other areas of high quality turf.
The first grub damage of the season usually appears about 5 to 6 weeks
after peak egg laying. In northern Illinois this would be August to
early September. The only damage these grubs do is prune off the roots
of bluegrass. It normally requires 10 to 12 grubs per square foot to
cause visible damage. It is not uncommon to detect 40 to 50 grubs per
square foot in favorable egg laying sites where heavy populations of
tan beetles were observed in July. In next month's newsletter I will
discuss control strategies.
Early Summer 1998
Vacations and the Yard &
Garden | Periodical Cicadas
| Bronze Birch Borer
| Moss Problems in Lawns
| Bug Bites—Grubs Are
Coming to Your Lawn! | Lawn
Care Calendar | Cybergarden
Sites | Hort Shorts
| Hort Tips | Food
Handling: Picnics, Barbecues and Outdoor Eating | In
the Kitchen: Persuading the Public | Locally
Grown: A Kitchen Herb Garden | Health
Update: Gardening in the Summer Sun
Index
| Feedback
