Only 2? How big?

where were the tree roots?

What product did you apply? Scotts, BioAdvanced, Andersons? There are a few. Not sure if they all have the same AI.

 

Only 2? How big?

where were the tree roots?

What product did you apply? Scotts, BioAdvanced, Andersons? There are a few. Not sure if they all have the same AI.

These are good points. Certain products are better than others.

For example, Spectracide Triazicide Insect Killer for Lawns - Granular (gamma-cyhalothrin 0.05%), though advertised as season long grub control, has been found not to kill grubs at any rate by a Mich State Univ research study. I've had great results with Talstar P imidacloprid. I imagine there are other good products.

(Edit: corrected from Talstar that I used for Army worms to imidacloprid that I used as grub preventative. Thx to @robjak for brining it to my attention (below). Apologies for any confusion.)

 

I used Bio advanced season long grub control.
The roots were from a tree I had cut down a couple years ago.

 

Thanks for the pics. AI is Imidacloprid. You should be good.

Was the grub alive? Was it found grass root zone?

 

Found a label for bioadvanced season long grub control with an AI of Lambda-cyhalothrin. it is a Pyrethroid.

I would not use this for Grub control.

So I found conflicting info for bioadvanced insecticides. Not the first time. Next time read the label and remember the active ingredient.

 

if you used the Lambda-cyhalothrin version:

"For grub control, except on dung beetle, treat any time between late July and early October."

Not exactly season long.

 

If you use Talstar P (bifenthrin), it is also a Pyrethroid but has a much smaller residual. Talstar P is not labeled to treat for grubs.

 

Good advice above and here is the article you should bookmark for future reference - many products that "list" grubs on the label don't do a thing to grubs … :
https://www.canr.msu.edu/news/how_to_choose_and_when_to_apply_grub_control_products_for_your_lawn

At this point you want to, as quickly as possible, put down one of the "curatives" listed in the article that will actually kill the grubs like, the night you put the stuff down and water / rain it in …