If parts of your lawn lift off like a toupee, grubs have been at work chewing grass roots. Grubs are larvae of Japanese (and related) beetles. The beetles lay eggs in turf from mid- to late summer, and the eggs hatch into grubs that feed on grass roots. Cold weather drives the grubs deep into the soil, but they surface again in spring before emerging as beetles.
These caterpillar-like grubs -- fat and creamy white -- are usually curled up when you find them. Incidentally, they're considered tasty morsels in certain parts of the world.
Rather than killing grubs by eating them, you could do them in by drenching your lawn with chemical pesticides. But if you don't want to think twice before sitting or walking barefoot on your lawn, there are several natural ways to keep grubs under control.
In Japan, the native home of Japanese beetles, natural enemies are so effective that the beetles are not even considered pests there. Two biological controls are milky spore disease and predatory nematodes. They are available from Gardens Alive! at (812) 537-8650.
If you can establish either milky spore or nematodes in your soil, control is long-lasting. Unfortunately, milky spore will not survive where winters are frigid.
An entomologist in Colorado devised a straightforward, mechanical approach to killing grubs. Strap a pair of long-spiked sandals to your shoes and stroll over your lawn. The three-inch-long spikes skewer grubs in the soil. Studies showed that a very thorough late spring or late summer stroll -- ensuring two spike penetrations every square inch of soil -- killed 56 percent of the grubs.
The sandals are marketed as Lawn Aerator Sandals and are available from Mellinger's at (800) 321-7444, and other sources.
A final approach to the grub problem is the do-nothing approach. Populations of Japanese beetles and their grubs fluctuate from year to year, and even in a given locale, there may be pockets of heavy or light infestation. So do nothing and you still might not have problems with grubs this year, or maybe ever again.
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