Wow excellent! I would love to hear more from you as the season progresses. Japanese beetles are such a terrible pest. I am done going outside with a soapy cup and pretty much try not to look at my plants after they arrive.

I'm with you on the Japanese beetles, so I'll be following the clay experiment. It's hard not to cackle evily as I round the yard with my soapy water.

6/26 and 6/27 update:

Was OOT for a few days and was worried about what I would find. Was encouraged to see two things on 6/27

1. Just ONE beetle on a 5 year Lady of Shallot shrub (new growth). There were also both flowers and buds that had opened, but they hadn’t been touched at all. That was really cool.

2. Beetles were attracted to the one pot/plant I didn’t spray—zinnias! I didn’t know they were into zinnias, too. So i promptly removed them (there were about 10-15). After removal, I sprayed them with clay and waited until the next morning (today) to see if there was any impact. I also decided to keep the leaves that were munched on to test whether or not the clay would cover the beetles’ pheromones/scent.

Today is 6/27, and I will report back on the 24 hour impact. It’s 2 pm CT now and the results are already encouraging—BUT my aim is to just collect data based on my experience and location. In checking last year’s photos at this time, the biggest fleet of beetles arrived around July 7th, so I am going to continue documenting throughout the season.

6/27 update:

I went out a total of 5 times yesterday. At around 2:00 pm (garden round #3), I only found two beetles seemingly dusted/covered in clay on LOS (a favored rose of theirs in my garden). Really interesting. Made me wonder if they had already been on the rose when I sprayed, or if the clay transfered onto them. Either way, I'm taking this as good news because I believe I read somewhere that clay can irritate their exoskeleton (I'll see if I can find the source). They were definitely acting a bit sluggish and dare I say loopy. I pruned the leaves they were on and also checked the rose for telltale signs of "beetle damage" (e.g., skeletonized leaves). Will attach a picture later.

At 6:30 pm (garden round #5), there were no beetles detectable or any additional damage whatsoever on any roses or other plants, including the mildly ravaged zinnias. I went out a total of 5 times yesterday. On my last round, I gently shook each rosebush to check if any would fly off (I also realize that they also bear down and drop, so this is not a perfect way to find out if they're indeed on shrubs). I did find another bagworm on a shrub, though, but I removed it and didn't find others. I sprayed all rose shrubs again just in case.

6/28 morning update:

Still no beetles as of 9:00 am this morning. It sprinkled a bit after I left for work, so I'll be interested to see how the clay held up and if the sprinkling when I get back home.

6/28-6/30 update:

Not much going on. Still can't tell if the clay is helping, if it's just too darn hot for them to be out in big numbers, or if they aren't really here yet to be accumulating in masses. I've picked off a max of 3 beetles a day since Wednesday, and most of the time, they are avoiding the roses and going to other plants. I found 1 on a sunflower leaf (which was sprayed, but maybe not completely?) and on a potted raspberry shrub that I forgot to spray.

I am also checking daily for signs of damage and presence (e.g., skeletonized leaves and poop), but so far, there's very little of it. Interestingly, I have exlusively found the beetles on leaves, never on buds or blooms, which is weird because LOS produces blooms too quickly for me to catch up to. I always thought they preferred the blooms! Still finding more bagworms than beetles.

I still try to spray every other day to ensure maximum coverage as new growth comes up.

My next task is to go around town and check the roses in city planters. If they look fine, I suppose it may mean that the JBs haven't fully arrived OR the heat is making it hard for them to get out of the ground.

Below are pictures of beetles found after I sprayed. Because they look like they have droplets of the clay on them, my guess is they might have been already on the shrub as I was spraying OR the clay was still dripping from an overhead leaf when they landed on the shrub.

Will report back if anything changes!

So far really good results

Thank you, everyone! @dianela7analabama I hear you on not looking at plants after they arrive. The JBs were so bad one year, they completely skeletonized by LOS shrub. I'm still haunted by the image!

@Ashley Smith zone 5a HA! The soapy water works so well, it's hard not to feel accomplished! One year, I must have cackled so hard myself that I tripped on a tree root, and the soapy carcass water went flying everywhere. I think that was the day that I ordered the WP Surround!

@Kristine LeGault 8a pnw I am really hoping this works. I'm bracing myself for the July deluge, but fingers crossed that this deters them even just a little bit...

@Kristine LeGault 8a pnw good to know that the clay confuses the pheromones! I am finding this to be the case since I don't always remove the damaged leaves before I spray the clay. I definitely do so if I find damage on roses, but I am more lax with the zinnias. I just spray the damaged leaves, and so far, this has worked!

Ooh yes--I forgot to mention how I apply it. I followed Surround WP's instructions and apply the suggested ratio of 1/2 lb clay mixed with 1 gallon of water.

7/1 Update:

It sprinkled overnight (0.15 of an inch) and rained on and off throughout the day (0.5 of an inch) after almost zero rain for over two weeks. I sprayed in the morning before heading to out to work, and but was fully expecting to come home to find more beetles now that it got cooler, and the ground being softer. Got home at around 7:00 pm to a double rainbow and absolutely no signs of JB damage and NO beetles anywhere. Every bloom and bud is intact. I checked every shrub twice in disbelief. We are getting more rain tonight so I didn't apply the clay. It will be interesting to see how the rain impacts beetle numbers tomorrow!

7/1-7/3 update

The clay held up fairly well to the rain (I was impressed). I've caught 3 beetles total per day between 7/1 and 7/2. I found a 2 doing the deed on a peony shrub--I didn't think they liked peonies, but I sprayed the peony shrubs just in case. They can do their business anywhere but MY yard, as far as I'm concerned (eye roll).

I am deliberately leaving unsprayed blooms on shrubs here and here as a test for my own curiosity. Today, 7/3, I caught 7 total, but 5 of them were munching on a juicy Earth Angel bud, and 2 were doing "supermans" on another shrub.

Additional note: I'm not seeing effects of the clay on midge, weevils, and bagworms. I've seen 1-2 cucumber beetles munching on blooms, but they are few and far between this year for me (I'm doing a heavy crop rotation this year--no nightshades, curcubits, beans, hollyhocks). I observe that the clay reduces grasshopper damage, though, by approx 50%. I'll take that!

Pictures of clay remaining after 0.5+ inches of rain overnight

Please keep us updated! This is very helpful to know.

I’ve been recommending Surround WP for many years, and not just for pest management. My heat and sun sensitive vegetables like tomatoes, eggplant, and greens prosper with applications in order to prevent sun scald and heat stress. That’s important for those of us living in the sunny South.

I want to add for information purposes that one MUST wear a mask, gloves, and eye protection when mixing and spraying this product. You do not it in your mouth, lungs, or eyes.

So far, the clay appears to be working well. It holds up quite decently even to heavy rainfall. I spray now every 2-3 days to coat maturing growth. I catch between 0-5 beetles per day (they are mostly under leaves or on new growth, so I am being careful to spray under leaves. There were none just now when I went to check my shrubs and other beetle-magnet plants.

The sweltering heat also made a comeback, so I don't know if this is also contributing to the beetles not being able to get out of the ground as easily. I've heard mixed reports on beetle numbers on Houzz. My MIL in mid MO has a healthy amount, but she's on a farm, and they just love her asparagus. AFAIK she has a no-spray garden and she prefers to handpick beetles into a can. I'm doing a crop rotation this year, so this could also be a reason for reduced beetle #s in my yard (I also don't live on a farm, but I do live a stone's throw away from several long nature trails.

FWIW, my neighbor has a fledgling pink Knockout that is 3/4 dead but there isn't a single beetle on it, whereas I've had beetles pass by for almost a month now. My sense is that IPM is working, but I will definitely be including Surround WP in my IPM toolbox! Will post last year's pics and this year's pics for comparison soon.

Thank you for your participation in this thread, I feel like it has really been informative for those unfamiliar with Surround WP. It It’s worth reminding people that it is OMRI listed for organic growing and safe to harvest same day as application.

Please keep up the reporting. I am not convinced there is an effective deterrent, but I want to learn more from your experiences with kaolin clay. About 90+% of beetles go to my buds and blooms, so spreading kaolin clay on all plant parts except the blooms would not stop my infestations. This year is the lightest since circa 2005, a few years after Japanese beetles appeared here, due to drought.

Mark, you could spray the Surround on the buds with no problem. A film of the product really inhibits feeding and egg laying, in my experience. It is effective with many kinds of piercing/sucking, chewing, and rasping arthropods.

Where do you find the clay? Is this something I can get locally?

@mark_roeder 4B NE Iowak, glad to hear that the updates are useful. It is truly odd that while the clay doesn’t stick well to the buds (new growth), JBs have rarely gone for the blooms. It could also be that I check my shrubs multiple times a day, and pick them off immediately. However, I have noticed minor JB damage on a bloom or two, but it’s super minor—as though they munched a bit and went, “meh, next”.

@Melissa Mc (6b) that is a great question. I think I got my 25 lb bag from Arbico Organics (online), so I’m not sure about local availability. It may be worth checking in with a few garden stores. Surely some place has got to have this elixir!

So I'd been OOT for several days, and was fully expecting at least a handful of JBs to be around since I wasn't around to do my usual daily rounds. BUT, I didn't see a single one this morning. By the afternoon, there was a downpour. The clay continues to stick fairly well--even after the downpour, about 50%-75% of the clay still clung to leaves/stems. After the rain, I found just one JB supermanning on one of my arborvitaes.

I was also at my MIL's farm this week, and she reported a pretty steep decline in the population since the JBs arrived in mid-June (she isn't using the clay yet). I think over the span of 2-3 days on the farm, I saw ONE hanging out on a squash leaf in her garden...I am really stumped!

So clearly, neither the clay nor the heat can explain what's keeping these critters at bay. I wonder if the parasitic wasps were effective last year, which may have impacted grub numbers for this year? Or maybe the JBs are just very delayed, and coming for our shrubs come August/September? I shudder to think of this scenario.

So I haven't sprayed in 6 days and it's rained a fair bit....so I suppose like clockwork, I found 5 beetles this evening. Ha! 3 on Lady of Shalott (2 on leaves, 1 in a bloom), 1 again on an arborvitae (I still don't understand what they are doing on them), and 1 that was chowing down on an unsprayed zinnia leaf. Well, I think I'm seeing a pattern that sprayed plants may indeed fare better!

Most of the summer we have had drought. The hard ground lessens Japanese beetle #s, as they cannot get out of the ground from the grub stage, and they cannot easily get back in the ground to lay eggs.

We had rain twice or so about one week ago. The grass greened up, and while we have some J-beetles, we have very few. I am spot spraying them with Bayer Rose and Flower Insect spray which has IMIDACLOPRID. By spot spray, I mean I only spray individual beetles, and it only takes a drop. I consider it a contact spray, but I notice if a new beetle alights on the same bloom, the new one which I didn't spray is often having convulsions when I take another look at night after work. It is not just the spot spraying that keeps #s at bay, it is the drought -- I do not see damage to my linden tree this year which attracts J-Beetles in the thousands.

I purchased BeetleJus to apply on my roses this year,which is an organic, but with so few Japanese beetles, I haven't sprayed it yet; I don't want to waste it when there are so few beetles and I would be unable to guage its effectiveness.

Welp. My curiosity got the better of me...I decided to continue my experiment of not spraying just for additional indications that the clay might be making a difference.

It has now been 12 days since I've last sprayed Surround. I went OOT again for work and got back home today to over 50 beetles munching on leaves and blooms. Only 1 rain since I've been gone. Beetle numbers are much lower than last year (I counted 120 one evening in 2022, along with a COMPLETELY annihilated LOS shrub) but this is still a notable increase in bettles compared to when I was spraying the clay regularly. Though not a controlled experiment, my observation remains that clay helps reduce bettle numbers. Now, I am wondering if I can reverse the effect with my previous spray program and dilligent deadheading...

I sprayed this morning. By the end of the day, I caught around 10-ish beetles. 2 under leaves, the rest in blooms. Not stellar, but also not 50! I plan to re-spray tomorrow or the day after. This Midwestern heat is insane.

Samuella, you do understand how this stuff works, right? Not as a pesticide but a crop protectant. A film of the product makes the plant unpalatable for plant feeders, makes the leaf surface undesirable for egg layers, makes the plant surface resistant to certain fungus diseases, and makes the plant resistant to heat stress, sun scorch, and dessication.

Spraying Surround WP directly onto Japanese beetles isn’t likely to kill them outright. I couldn’t tell for sure from reading your reports if you were wanting to kill the beetles or deter them.

@rhizo_1 (North AL) zone 7 Thanks for following my updates, but I'm not sure what you mean by your comment. I haven't implied in my updates that I spray Surround "directly" onto beetles, and nowhere have I mentioned that I am trying to "kill them outright" by using Surround. To the contrary, I've documented my use of Surround with words like "coverage" using direct references to leaves, stems, maturing growth, and buds. If you're referring to the update from 6/28-6/30 where I showed a few photos of the beetles with clay droplets on them, I used the verb "found" in reference to the beetles, which implies I was not aware that they were there when I initially sprayed. I've also discussed the point of palatability in reference to other insects (bagworms, grasshopers). I hope this helps clarify things!