By Mike Isbell
University of Georgia
That somebody is going to have to use a magnifying glass, too, which makes the grub's rear end look even bigger.
Lately, I've had a lot of calls about crows and even wild turkeys digging up turf grass looking for stuff to eat. In a lot of these cases, the birds are digging for grubs in the soil.
Moles, skunks, raccoons and armadillos, as well as birds, all can root up the turf hunting for grubs. And even if animals aren't digging, the grubs themselves can damage turf grasses.
Damage symptoms
Most grubs feed on grass roots, cutting the plants off from water and nutrients. Damage from grubs appears as yellowing or browning of the leaves, signs of drought stress even when there's moisture, and loose turf that pulls easily from the soil.A typical phone caller will say something like, "Mike, I was out mowing my lawn and my mower just tore up the grass by the roots."
Sounds like grub damage to me.
Grubs feed most actively and are easiest to control during late summer and early fall. But they may be active in warm periods throughout the winter.
Main culprits
More than a dozen species may damage turf in the Southeast, but the main ones we have are green June beetles, chafers, Japanese beetles and May beetles or June beetles.While white grubs in general are among the hardest turf pests to control, the green June beetle grub is one of the easiest. Because they come to the surface at night, green June beetle grubs come in contact with insecticides more readily than the other grubs that remain deeper in the ground.
To check for white grubs, cut three sides of a square foot of turf with a shovel. Then fold the sod flap back and look for grubs in the top 2 or 3 inches of soil and roots.
Some species can damage turf with just four grubs per square foot. Others can have 10 to 20 per square foot and still not damage turf.
Which grubs?
If you find white grubs in your soil, how do you know which one it is? Well, if it crawls on its back, with its legs sticking up in the air, it's a green June beetle. I'm not making this up -- they do crawl on their backs.If they don't crawl on their backs, that's when you use your magnifying glass. But you have to be willing to get close, and you have to know what you're looking for. It's not for the squeamish.
With an identification key available from the Extension Service, you can identify the grubs you find. If you can identify them, your county agent can tell you what to use to control them.
You don't have to be an entomologist to identify a grub. But a proctologist? Maybe.
(Mike Isbell is the Heard County Extension Coordinator with the University of Georgia College of Agricultural and Environmental Sciences.)
