Las Cruces Yard Guide

Lawn Grubs, Grub Treatment and Other Lawn Pests in Las Cruces

When a Bermuda lawn browns in patches, people often blame bugs. Usually it’s water. But sometimes grubs are eating the roots, or armyworms chew through the lawn after a monsoon storm. Here’s how to tell whether pests are really the problem, check for them in five minutes, and treat only when it’s worth it.

Updated September 2026 using NMSU and Colorado State University Extension guidance.

Lawn care Las Cruces NM - freshly mowed and edged front lawn in front of a two-story home
  • Most brown spots are water
  • Grubs: turf peels like carpet
  • Armyworms: after monsoon rain
  • Check before you treat

Quick answer

How do I know if grubs are killing my lawn?

Tug on the grass at the edge of a brown patch. If it peels up like carpet with few roots and you find C-shaped, creamy white grubs with brown heads in the soil, grubs are eating the roots. Animals digging in the lawn are another sign.

If the grass holds firm and the soil is dry, the problem is water, not grubs. Check that first; it’s the most common cause of brown patches in Las Cruces.

Which lawn pest is it?

What you see

Likely pest

Turf lifts like carpet, C-shaped grubs

White grubs

Grass chewed down fast after rain

Armyworms

Stems break at base, sawdust-like frass

Billbugs

Holes dug by skunks or birds

Grubs below

Dry soil, grass holds firm

Not bugs: water

White grubs

What are lawn grubs and when do they cause damage?

White grubs are the larvae of scarab beetles like masked chafers and May or June beetles. Adults lay eggs in early summer, and the grubs feed on grass roots through late summer and fall, when damage shows up as brown patches that don’t respond to water.

What do grubs look like?

Creamy white, C-shaped, up to about an inch long, with a reddish-brown head and three pairs of legs.

Why does the lawn look dry?

Grubs eat the roots, so the grass can’t take up water and looks drought-stressed even when watered.

Why are animals digging?

Skunks, raccoons and birds dig up lawns to eat grubs, which often reveals the problem.

Grub identification, life cycle and thresholds from Colorado State University Extension, Billbug and White Grub Management in Lawns. Local pest list from NMSU Circular 607.

Check first

How do I check my lawn for grubs?

Cut three sides of a one-foot square of turf at the edge of a brown area, fold it back and count the grubs in the top few inches. Colorado State notes nine or more masked chafer grubs per square foot can damage stressed turf.

1

Pick the edge

Sample where brown meets green, where grubs are actively feeding.

2

Cut a flap

Cut three sides of a one-foot square about 2 to 3 inches deep.

3

Fold and count

Peel it back and count grubs in the roots and top soil.

4

Check a few spots

Sample two or three areas for a fair average.

5

Put it back

Press the sod back down and water it.

Treat

How do I get rid of lawn grubs?

Treat only if counts are high. Beneficial nematodes, which NMSU recommends for white grubs, are a low-toxicity option. Preventive products go on around midsummer egg hatch; rescue products target active grubs. A grub treatment service can count grubs first and time the treatment. Always follow the label.

Option

When

Notes

Beneficial nematodes

When grubs are active; moist soil

Low toxicity; apply in evening and water in

Preventive grub control

Midsummer, around egg hatch

Stops young grubs; follow the label

Curative (rescue) control

Active feeding, late summer

For heavy infestations found by sampling

Better lawn care

All season

Deep watering and correct mowing help lawns recover

Does overwatering attract grubs?

Moist soil during egg-laying helps grub survival. Deep, less frequent watering is better for the lawn and less friendly to grubs.

Will the lawn recover?

Bermuda usually recovers once grubs are controlled, with deep watering. Badly damaged patches may need re-sodding.

Other pests

What other pests damage lawns in Las Cruces?

Armyworms can strip a Bermuda lawn in days, often after monsoon rains in late summer. Billbugs damage Bermuda at the base of the stems. Both are less common than grubs or watering problems, so confirm what you have before treating.

How do I spot armyworms?

Grass chewed down in spreading patches, often with birds feeding. A soapy water drench on a square yard brings caterpillars to the surface.

How do I spot billbugs?

Stems that break off easily at the soil with sawdust-like material at the base. Adults are small snout beetles.

Are there biological options?

NMSU lists Bacillus thuringiensis and parasitic wasps for armyworms and nematodes for billbugs.

Prevention

How do I prevent lawn pest damage?

Keep the lawn healthy: water deeply and less often, mow Bermuda at the right height, fix sprinkler gaps, and avoid heavy nitrogen in late summer. Healthy turf tolerates more grubs, and dry surface soil in early summer reduces grub survival.

  • Deep, less frequent watering
  • Correct mowing height for Bermuda
  • Even sprinkler coverage
  • Sample before treating anything

Still brown? Work through our brown lawn causes and fixes and the Bermuda lawn care guide.

Lawn grub FAQs

Brown patches that peel up like carpet, with C-shaped white grubs in the soil below. Animals digging in the lawn are another clue.

Colorado State University Extension notes about nine or more masked chafer grubs per square foot can damage stressed turf. Healthy lawns tolerate more.

Mostly late summer and fall, after eggs laid in early summer hatch and the grubs feed on roots.

NMSU lists beneficial nematodes as a biological control for white grubs. They need moist soil and should be applied in the evening.

Preventive products go on around egg-laying and hatch in midsummer. Rescue products are for active grubs found by sampling. Follow the label.

Caterpillars that chew grass down quickly, often after late-summer rains. A soapy water drench brings them to the surface.

Usually, once grubs are controlled and the lawn is watered deeply. Dead patches may need new sod.

No. In Las Cruces most brown patches come from dry spots and sprinkler gaps. Check water and coverage first.

Not sure what’s eating your lawn?

We check water, coverage and pests, and only recommend treatment when your lawn actually needs it. Free, written estimate.

  • We call back the same business day
  • Free, written, itemized estimates
  • One-time jobs welcome; no contract
  • Serving Las Cruces, Mesilla and Doña Ana County

Las Cruces Landscaping Group
1921 Santa Ines Drive, Las Cruces, NM 88011
(575) 270-0676. Mon to Sat, 7 a.m. to 7 p.m.

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