The best way I have found to control Japanese Beetles non-chemically is: Half-fill a cup or small jar with water and add a few squirts of dishwashing liquid (I use Dawn). At the beginning and end of each day walk slowly through the garden and brush the Japanese Beetles off the plants and into the water (or pick them off and throw them in — they don’t bite). As I’m doing this I inspect the plants for any insect damage, new fruits, etc.
For alternative Japanese Beetle control solutions please see the box to the right.
Japanese Beetle on Brandywine Tomato Plant
That is it! There is no magic trick and this isn’t rocket science. It just takes a little effort on your part and you can probably keep damage to a minimum. So if you came here looking for a solution to the Japanese Beetles that are mating and feasting on your vegetables there it is — now scoot and get to drowning them!
If you are interested in learning more Japanese Beetle Information please continue reading:
In my Zone 5b area of Ohio Japanese Beetles begin their invasion in June and it lasts until about August or so. Every year is a little different. What isn’t different no matter where you live is that Japanese Beetles are very destructive and are difficult to control. Oh, and they LOVE vegetable plants…
A nice summary of information about Japanese Beetles can be found in this Wikipedia entry. The rest of this page will contain some of my own observations, and hopefully over time those of others who stumble here.
Detection: There are 2 easy ways to detect when the Japanese Beetles begin invading your garden. The easiest way is just to look around and see them sunning themselves on leaves. Fortunately they are quite large and their coloration stands out very well against the green backdrop of the plants. They are usually at or very near the top of the plant. After a while you can even spot them as they clumsily fly around from plant to plant — or more often than not you can hear their distinct low-pitched buzzing as they fly.
Japanese Beetles Mating and Eating Leaf
The second way to tell if you are being invaded is by looking for their distinct damage pattern they leave after eating a plant. They eat the “meaty” part of the leaf, but leave the stem and veins intact. It kinda reminds me of what a plant’s skeleton might look like. And they begin eating at the top of a plant and work down, so the damage is usually easy to spot.
The Japanese Beetles in MY garden seem to especially like Green Beans, Eggplant and Yellow Marigolds. However, they must not be too picky because I have found them on literally every type of vegetable plant in the garden!
Control: Because Japanese Beetles can fly long distances it is just about impossible to completely eliminate or control them. What I try to do personally is just minimize my losses. As mentioned at the top of this page the most effective non-chemical means I have found to keep the population in check is to manually pick and drown them.
A few notes about picking them are in order. They DO fly so you have to be a little quick. BUT they fly VERY slowly and clumsily so you don’t need to be a speed freak or anything to effectively capture them. If you put the cup of water in front of them they often fly right into it — which can be quite satisfying! They also kind of cling to your fingers when you pick them up. They don’t bite or hurt you at all, but their legs seem a little sticky or something, so at times you need to literally wipe them off against the edge of the container.
One funny thing you will notice is when you get near a Japanese Beetle is it will raise 2 of it’s hind legs up into the air. It is probably some sort of threat move meant to drive away potential predators. But every time I see it I crack up because it looks like they want to box you with their little legs… Yes, maybe I spend a little too much time in the garden with these Japanese Beetles… At any rate, when they display this “threat” move I often just pick up the beetle by one of the legs it conveniently raised up for me and plop it right into the water!
A little internet research reveals why dishwashing detergent and water is so effective at killing these suckers. Apparently bugs breath through their bodies! The dishwashing detergent coats their skin with a film that prevents them from “breathing,” thus quickly suffocating them. Who knew?
If you just want to chemically control them Sevin will do the trick. I tried it once and it killed every insect in my garden for days, so it is quite effective! Having said that, I won’t be using it or any other pesticides or herbicides in my vegetable garden ever again for 2 reasons: I have to assume that whatever I put on my plants ends up in my body when I eat those plants, and if a chemical is deadly to a bug how can I be 100% sure it is safe for me? Also I wonder how a pesticide that works on over 100 pests can distinguish between a bad bug and a good bug — like a ladybug perhaps? Or a bee? Food for thought isn’t it?
The Bt and Milky Spore options of controlling Japanese Beetles interest me but there really isn’t a ton of information about them out there that I can find. And in the back of my mind there is always this thought that no matter what I do on my property to control them, if my neighbors don’t do the same thing then a Japanese Beetle can just fly over from their property and I am stuck picking them off by hand again. Just like I am doing now.
If anyone would like to add any information please enter it into the comments below. I’m especially interested in posting a photo of a plant skeleton so everyone can see what the damage looks like.
