Will they lay eggs and create a grub problem?

Yeah, they're just coming into season here, 30 miles north of you. I've seen them mating on every available surface (and sometimes precariously clinging to unavailable surfaces!)

They could cause an issue as the grubs happily consume roots (grass roots being a favorite). During the summer, the grass isn't growing much root at all, so they do damage.

Fall and spring they're still there, you just don't notice 'em so much unless they're really bad.

You could use something nasty--like GrubX--to control them. Alternately and more organically, Milky Spore is great in our area and doesn't kill everything it touches.

However, it does take some time to build up to killing levels in the lawn. Once it does, it lasts a good, long while.

Yes, they will lay eggs and give you grubs. If I were you, I would put down Bayer 'Complete Insect Killer for Soil and Turf' asap. If you've got swarms of beetles, you've got problems that need immediate attention! Don't fool with Milky Spore.

Then, next year in the beginning of June, be sure to put down some grub control product. Preferably something with Merit in it like Bayer 'Season Long Grub Control'. That'll prevent whats happening to your lawn this year.

Interesting. So these guys are here to lay eggs, not just eat grass and leaves.

I didnt see any of them on the lawn yesterday afternoon - just on my trees. I know there's stuff to spray the trees as well. This is my third summer in this home and never had these problems before.

Thanks for the help!

Interesting. So these guys are here to lay eggs, not just eat grass and leaves.

Yep, eat and reproduce. That's their cycle as an adult. As a grub, their cycle is eat and grow to become adults.

It can't possibly be all that interesting. But there you go.

Certainly you can use an insecticide if you like, although killing the grubs is best as it breaks the cycle. Also, the grubs are much easier to kill than the adults are.

Besides, new adults just fly in after the food.

In defense of Milky Spore, it does take a bit to build up. I noticed a serious reduction in populations of grubs my first year, and now (the second), they're almost gone. So it's not that long, and I don't constantly have to reapply.

In defense of the pesticide route, it kills 'em dead pretty fast. Problem gone.

Thanks. Im gonna hit it with the pesticides tomorrow - whatever I can get my hands on at HD.

Am also going to order the Milky Spores online from Yardiac.com - from what I've learned, once this stuff takes hold it can keep grubs away for up to 25 yrs?

Oh, and from another thread - supposedly Japanese Beetles (JB) dont travel too far? So, if I can irradicate the grubs on my property, and some of my neighbors on either side, I wont have to worry about JBs from the rest of the neighborhood?

Am also going to order the Milky Spores online from Yardiac.com - from what I've learned, once this stuff takes hold it can keep grubs away for up to 25 yrs?

Theoretically, and usually more north of us. I'm not counting on more than ten years of coverage. Long-story-short, over time the spore generations micro-evolve into something that has less tendency to kill the beetle and more tendency to infect without killing. The spore gets a home for much longer and the grub doesn't die.

The longer the growing season, the more cycles the spore can go through and it has more time to mutate and select. That equals less time on the coverage.

When you start seeing grubs in 2017 or so, just apply it again.

Oh, and from another thread - supposedly Japanese Beetles (JB) dont travel too far? So, if I can irradicate the grubs on my property, and some of my neighbors on either side, I wont have to worry about JBs from the rest of the neighborhood?

Grubs have limited travel as they have to crawl through soil. The beetles can fly (kind of poorly but they manage) so a clear field with plenty of food will attract them. Put out a beetle trap and you'll get every beetle within a thousand yards.

Even with my defenses, I still have beetles. Lots of beetles. They wing in from all the surrounding properties in a search for food, and then stop to lay eggs in the soil.

The populations are so stunningly high and dense that there's not much you can do about it. The best you can do is keep the grubs down on your property and limit the damage.

Just another note -

Besides applying chemicals or milky spore, one of the best long term controls is proper watering. The beetles love to lay eggs in moist soil. If you are watering frequently, you will be their best friend. If you limit your watering to once a week, your lawn will be much less inviting.

At this point though, you are already swarmed, so you will probably want to use one of the grub killing granuals to keep the problem from getting out of control.