Beetle Grugs Infestation (Edited)

[Derelict]

Newbie Tom back again.  This year I planted about 40 pepper plants and, after some fits and starts, most are doing well.  Yet, in an earlier post I noted that my Fatali pepper plants were ailing, just one container with three plants.  I got a few fruits from each of the three plants but it's been a big disappointment. 
 
Two of those three plants were dead and brown this morning, so I pulled them up.  I was shocked at how small the root ball was 5 months after planting.  See 1st photo.
 
But I was even more shocked at the two huge worms that came up with the plant.  I did some homework, and they are beetle grubs. 
 
So I continued to dig underneath that dead, withered, emaciated plant, and lo and behold!  I dug up about 30 huge grubs JUST IN THE FIVE-INCH COLUMN BENEATH THAT SINGLE PLANT.    The container is half wine barrel;  I would expect that there are probably hundreds more inside that container's soil.   See 2nd photo.
 
So this begs many questions, each of which I could use an answer for:
 
1.  I recycled some soil from last year, is this one of the reasons why I have a grub problem?
 
2.  Will the grubs only eat the living plant above the surface, or will their presence underneath also retard the root growth underneath?  If so, that would explain a lot.
 
3.  I have not had a hornworm infestation this year, I think, because I planted bird feeders around the pepper garden and the birds are constantly on the fence around the garden, looking in, when the dogs aren't pestering them.  But the birds will be ineffective against grubs, right?
 
4.  I have a few other plants that have been less than productive as well;  they just haven't responded as well as the majority of plants.  Assuming that the soil in those pots too are infested with grubs, what do you recommend I do this late in the growing season to protect my plants?
 
5.  Next year, what should I do to prevent cutworm infestation, and what should I do throughout the growing season to check for grubsand to control them?
 
Thanks for setting me straight!
 
Tom aka Derelict

 

[Downriver]

Not a great pic, but those look (and sound) much more like a beetle larvae, aka a "grub". Cutworms look more caterpillar-ish.
 
Here on the East Coast, Japanese Beetles are our grub makers. We treat with beneficial nematodes or Milky Spore.
 
ymmv

 

[Derelict]

Not a great pic, but those look (and sound) much more like a beetle larvae, aka a "grub". Cutworms look more caterpillar-ish.
 
Here on the East Coast, Japanese Beetles are our grub makers. We treat with beneficial nematodes or Milky Spore.
 
ymmv

 
Yes, they are grubs!  [I edited my post to be correct.]   Is having so many unusual?   And see my original questions, do I have them because I recycled the soil?

 

[Mr.joe]

I found what I believe to be grub worms in my yard this year. In my case they were in the ground no reused soil. I was also impressed with how many I could find. I believe they come from eggs layed this year? I could easily be wrong, I haven't actually studied the life cycle of a grub.

 

[solid7]

By far, the very most common beetles that we will find in the continental US, are May and June beetles.  Japanese beetles are also common, but the other two are the worst.  I've lived in both extreme ends of the country, and have seen them everywhere inbetween. (home comforts are the best, ain't they?)
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Here's the thing that's common to them:  They fly.  They lay their eggs where they will.  And they do it multiple times.  If you've got an area in your yard that holds moisture, that's where they'll head for. (the eggs need moisture to hatch)
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If you think re-using container mix is the issue, then consider that they'll find their way into the container through the drain holes, if it's sitting on the ground.
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Also, those are not cutworms in the picture you have shown, then are grubs.  Grubs and cutworms are not the same thing.
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Grubs will kill your plants from the roots.  They will never touch a leaf.
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As stated in the other post, Neem drench in the container will take care of the problem.  Do it every 4 weeks.