Yep, those holes are courtesy of the armadillo after your grubs AND earthworms. I never heard of hoplia but did find scarab beetles last year when I googled. Their grubs looked just like my grubs - fat and ugly. I take glee in popping them on my shovel when I'm digging. I've seen a couple of beetles so far, but it's early. I may get those nematodes. I looked last year but didn't bite on them. Also, I'm going to start carrying a latex glove in my pocket when I go out in the garden. Can't stand touching those things, but I do have the intense need to kill them. What really grossed me out today were two humongous stink bugs (big footed leaf bugs). My gosh, they were 4 times bigger than the ones last year. They could make a horror movie out these things. I killed one but the other got away. Drat! They were at least an inch and a half long. Gag me! Sherry

I think you are referring to Japanese beetles, they are stout greenish metallic. Unfortunately,there is no really effective way of dealing with them. Some snip all the buds and blooms off during the beetle season (June and July in my zone) because they ruin them anyway. Pesticides really don't work because they have to ingest it therefore consuming your roses in the process and killing bees and beneficial insects. I (and many here) go out several times per day and knock them off the flowers into a container of soapy water(soap added is the key,otherwise they can swim for days!) You won't get rid of all of them but it will help control the population. Others report milky spore applied to your lawn will decrease numbers by killing the larval stage-grubs, but it takes a couple seasons to see a noticeable difference. Avoid japanese beetle traps sold at retailers, they are reportedly so effective that they attract even more beetles to your yard to munch on your plants.Okay, long response but these are my most hated pest! In short,drown them and get rid of flowers for the short term.

Trust me, if you see adult JBs, then you have grubs in your lawn. Even if they ALL flew in from somewhere else this year (not likely), if even one female survives she will lay eggs in your lawn and you'll have grubs NEXT year. That's what JBs do; eat, mate, lay eggs. Every female that visited your roses before you applied Bayer already has eggs in your lawn. *Shudder* Milky spore is expensive, but it DOES work, and I've noticed a reduction in the JB population from year to year. But any more than zero are too many :P John

Don't chance it, just pot them for a few years to get them well established first with stronger root system. They will have a much better chance! Does look similar to black lawn beetle larvae, because of the smaller holes? Larvae looks like a big white hairless caterpillar curled up. Found if you dig deeper. Destroy in larvae stage with granular killer.