Understanding home lawn grub control products

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

I have noticed dead patches in a number of yards along my way to and from Michigan State in the last two weeks.  The rain we have had the last few days will make it very clear where there are grubs actively feeding because healthy turf will green-up quickly but the grub damaged areas won’t.  Dead patches in lawns – especially lawns with sandy soil and areas that have a slope to them are likely places for grubs to be active now.  If you see a dead patch, dig up a few shovelfuls of soil at the edge of the bare spot and look for 5/8 inch long, c-shaped grubs.  These are more than likely the larvae of European chafer if they are found in non-irrigated turfgrass.  European chafer grubs can appear unexpectedly and devastate a lawn with no warning as the adults are active at dusk during late June and early July and can easily be overlooked. 

I recently sent one of my able assistants to four of the local lawn and garden centers to see what kinds of products are available that specifically claim to work for grub control.  She noticed a considerable amount of overlap between brands and active ingredients and products carried by different distributors.  Since curative grub products, preventive grub products and snake oil were all in the same areas of these stores, I suspect a large number of homeowners have bought and applied things that will not do what they thought they would. Several of the bags had claims on them that are a little inflated.  The assumption that any product claiming to kill grubs will really work is wrong. The first critical issue is to determine what active ingredient the product contains by looking at the label.

Do not use products containing only one of the following: lambda-cyhalothrin, bifenthrin, deltamethrin, cyfluthrin or permethrin. Products containing these ingredients will not work for grub control when applied to the soil surface as the active compound will bind with organic material and will not move down to where the grubs are feeding. These products work well for turf feeding insects that live on the grass leaves or soil surface, but not for insects that feed on the roots. There are a few combination products that also include imidacloprid – read on to the next paragraph.  I found a product called Triazicide (containing lambda-cyhalothrin) and two others called Soil & Turf Insect Killer Granules and Ant, Flea & Tick Eliminator (both containing permethrin) in my two stops.

Products containing imidacloprid or halofenozide will not control grubs in the spring. They are preventive products and do not work well for large grubs. Although the bag often says apply anytime from May to Aug 15, it is highly recommended that these products be applied and irrigated into the soil during the first two weeks of July.  If applied now, they will have little effect on the grubs currently in the lawn.  I specifically saw Scotts Grub-Ex, Bayer Advanced Season Long Grub Control w/Merit, Bayer Advanced Complete Insect Killer (which contains both imidacloprid and cyfluthrin), a product called Grub and Lawn Insect Control and Spectracide One Stop Once & Done that contained one of these active ingredients currently in stores.  If applied in early July and watered into the ground, these products will give 90 to 100 percent grub control.  They will cost $140 - $250 to treat an acre of turf.

What to use now

Any products that contains carbaryl (Sevin) or trichlorfon. 

(Dylox) will work well when applied in the spring (from March to mid-  May) or in the fall (September 1 to November 1). These are considered curative compounds as opposed to the preventive compounds mentioned above and will kill the grubs currently in the ground.  It is necessary to irrigate after applying any curative product to get the chemical to the grubs. Run a lawn sprinkler for at least 60 minutes over treated areas (enough to fill a bucket 1/2 inch deep). It will take 10 to 14 days for the grubs to begin to die. One trichlofon product called Bayer Advanced 24 Hour Grub Control states that it will kill grubs in 24 hours, however, I doubt that any of the insecticides will kill grubs in the soil in much less than 5 days unless there is a Noah style rain and very warm temperatures. Do not apply any curative compound after May 15 as the grubs stop feeding in late May.  These “curative” compounds will typically give 65 to 85 percent control of grubs and will cost $150-$303 to treat an acre.

In summary

  • Check the bag to determine what active ingredient the product contains.
  • Do not use products containing only lambda-cyhalothin, bifenthrin, deltamethrin, cyfluthrin or permethrin for any phase of grub control.
  • Do not use preventive compounds such as halfenozide or imidacloprid now. Use them during the first 2 weeks of July to control grubs that would be damaging turf in the fall.
  • To kill grubs in the spring ­use carbaryl or trichlorfon and irrigate.
  • Always wear rubber gloves and rubber boots when applying insecticides to turfgrass.  Make sure and irrigate the lawn with at least ½ ofwater and allow the grass to dry before allowing anyone (or pets) into the treated area.

A short list of products now being sold for grub control

Sevin-Lawn Insect Granules (20 lb bag)
Made by Garden Tech
carbaryl 2.0%
9 lb/1000 ft2
Apply in spring or fall to active grubs.

Eliminator - Lawn Insect Killer Granules w/Sevin (20 lb bag)
Made by Gro Tec Inc
carbaryl 2.0%
9 lb/1000 ft2
Apply in spring or fall to active grubs.

24 hr Grub Killer Plus “contains Dylox” (15 lb bag)
Made by Bayer Advanced
trichlorfon 6.2%
3 lbs/1000 ft2
Apply in spring or fall to active grubs.

Complete Insect Killer (10 lb bag)
Made by Bayer Advanced
cyfluthrin 0.05%/imidacloprid 0.15%
3 lbs/1000 ft2
Apply in early July.

Grubex (14.35 lb bag)
Made by Scotts
imidacloprid 0.2%
2.87 lb/1000 ft2
Apply in early July.

Season Long Grub Control w/Merit (14.35 lb bag)
Made by Bayer Advanced
imidacloprid 0.2%
2.87 lb/1000 ft2
Apply in early July.

Grub & Lawn Insect Control (15 lb bag)
Made by DowAgro
halofenozide 1.5%
3 lbs/1000 ft2
Apply in early July.

Grub Stop Once & Done
made by Spectracide
halofenozide 1.5%
3 lbs/1000 ft2
Apply in early July.

Ant, Flea and Tick Eliminator (25 lb bag)
Made by Gro Tec Inc
permethrin 0.5%
Will not kill grubs at any rate.

Triazicide Once and Done Insect Killer Granules (10 lb bag)
Made by Spectracide
lambda cyhalothrin 0.1%
Will not kill grubs at any rate.

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