“If You Build It, He Will Come!” IV AKA Moles or Golf Holes? Which? Neither!

Adult White Grub

Hello Collinwood Family,

Ah, the dog days of summer.  Little League Baseball, Preseason Football, Major League Baseball Teams push towards pennant races and the last bit of heat and humidity before we are “jolted” into the reality of  harsh winds that turn into snowy cold days filled with hot chocolate and the warmth of the Holidays.  Oh, and how can we forget golf outings on are very own lawns.  Putting on the eighteenth hole to beat Arnold, or Jack or Tiger for the US Open Championship.  What?  You mean those holes that are on your pristine lawn or not manmade?  Of course they are not.  They are dug by those wonderful skunks in our area foraging for food.  And what have they found to entice their never ending appetite?  THE GRUB. 

You know the tell tale signs.  You water.  You weed.  You feed.  And yet your lawn fails to have the lush appearance so desired by man and beast.  Brown spots appear everywhere and let’s not talk about the “holes”.  Who’s been digging in my back yard and front yard and every yard in between?  Ah those pesky skunks looking for the even more pesky GRUB.

White grubs may be the most damaging turf insect pests in the United States. According to the U.S. Department of Agriculture, Japanese beetle grubs alone cause an estimated $234 million in damage each year— $78 million for control costs and an additional $156 million for replacement of damaged turf.

Japanese beetle and masked chafer adults are attracted to turf with moist soil which means they are especially attracted to lawns that get watered during hot dry spells. During the feeding period, female beetles intermittently leave plants, burrow about 3" into the ground— usually into turf— and lay a few eggs. This cycle is repeated until the female lays 40 — 60 eggs. Moist soils are certainly easier to dig through than hard, dry soils. Eggs will dry up and die under very dry soil conditions. The eggs also die when soil temperatures are around 90°F. Higher soil temperatures are typically associated with drier soils, as well as high air temperatures.

White grubs are the larval stage of many different beetles, including the Japanese beetle. The grubs live below ground and feed on the roots of tender grass plants that soon kill the plant. They are most destructive mid-late summer, but the damage they cause may not show up until early fall and by then, it's too late.

Lawns having numerous white grubs soon will show signs of injury. If browned areas haven't recovered once cool evenings return with adequate moisture check for white grubs 1" — 2" below the surface. Damaged grass areas will typically just peel back when pulled or raked. When the grass is pulled back you'll probably notice one or two white grubs, but with a little scratching, you'll soon uncover quite a few. The threshold for lawn damage is 5 - 6 grubs per sq. ft. which means that if you have more than 5 grubs in a square foot area, you'll see extensive lawn damage.

Once the damage becomes visible, it's too late to control. Damaged white grub areas will not recover as the plant and root system is dead. Before making repairs the grubs will have to be removed either chemically or by hand. Manually removing the grubs is not hard once the dead grass is removed.

If you have white grub damage and want to make repairs to those areas in the fall, you'll want to make sure that the grubs are under control before making repairs. Just over seeding these damaged areas without removing the grubs will not be successful as the white grubs will soon eat the new grass seedlings roots.

Products labeled for use earlier in the season (MERIT) won't control white grubs in the fall. Products containing trichlorfon (Dylox) and carbaryl (Sevin) are faster acting insecticides and will kill grubs in 3 — 5 days. Bayer makes 24 Hour Grub Control which contains Dylox. Be sure to read label directions on white grub control products before purchasing. Treated areas should be watered to at least 1" deep before application of the chemicals and then after application another 1/2" of water should be applied.

Once the white grubs have been treated or removed you can then proceed with making repairs. If you have large damaged areas, slice-seeding may make sense. If areas are smaller, use a lawn rake or hand claw tool to scratch the surface of the dead grass. Loosen the soil with the claw. If necessary add a little additional soil / peat moss, reseed and keep evenly moist.1

So remember family the only “holes” on our lawns belong on real and true Golf courses.

Until Next Time Happy Planting Collinwood Family.

Sincerely,

DPD J

Footnotes:

[1] www.american-lawns.com/insects/grubs.htmlezinearticles.com/