White grubs live in the soil and look like pudgy little cream puffs. But don't let that fool you. What they can do to your lawn isn't a pretty picture.
"The turf will yellow and die in large patches," said Beverly Sparks, an Extension Service entomologist with the University of Georgia College of Agricultural and Environmental Sciences.
Wait -- it gets worse. By the time you start seeing signs of white grub damage, Sparks said, it's very hard to control the insects.
"The damage doesn't really start showing up until late in the fall, about the time the turf starts going dormant," Sparks said. "Most of the time, homeowners don't even notice until spring, when the turf doesn't green up."
A dead giveaway that you have white grubs is the presence of birds, skunks or armadillos digging in your yard.
"On golf courses, sometimes the skunks or armadillos do more obvious damage than the white grubs," Sparks said. "One armadillo can just make a mess of a big area of turf."
Ready for some good news? There is some, if you act now.
"You need to start checking right now to see whether you have white grubs in your lawn," Sparks said. "Now is the only good time to treat them. If they're out there, they're small now. They're not doing a lot of damage yet, and they're much more susceptible to the products we use to control them than when they get larger."
|GRUBS LIVE IN THE SOIL so checking for them requires getting into the soil. Cut three sides of a square of lawn and pull it back to look for white grubs. When treating for grubs, be sure to water the insecticide in thoroughly to get it to the insects 2 or 3 inches deep in the soil. (Photo courtesy the UGA College of Agricultural and Environmental Sciences.)|
To check for white grubs, "take a shovel and cut on three sides of a square foot of lawn turf," Sparks said. "Then fold that flap of sod back and look for grubs in the top 2 to 3 inches of soil and the grass roots."
Do that in three to five places around the lawn. Then divide the total number of grubs you find by the number of sites you tested.
"If the number of white grubs averages five to 10 or more per square foot in nonirrigated turf, you need to get them identified," Sparks said.
White grubs are the larvae of Japanese beetles, green June beetles, May and June beetles and chafers. The county extension agent can help you identify the species you have.
Some of those species, Sparks said, have much bigger appetites than others. Some can wipe out patches of turf with just four grubs per square foot. Others do little damage with as many as 20.
For homeowners, the best insecticides to use are granulated forms of diazinon, chlorpyrifos (Dursban) or isofenphos (Oftanol), Sparks said.
Others registered for home use include trichlorfon (Proxol) and bendiocarb (Turcam).
Whatever you use, water it in well. "You have to get it down through that turf 3 to 4 inches into the soil," Sparks said. "Because they're in the soil, white grubs are hard to control. If you don't deliver the insecticide down there, you don't have a chance to control them."
(Dan Rahn is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)