Experiment: July 1st - First Japanese Beetle

[canadian-gardening]

-
Today I went to check the garden and I saw my first Japanese Beetle on the grape leaves.
Last year - they ate the grape leaves, plums, raspberries, white birch and roses.
So, tomorrow is open season on Japanese Beetles.
What do you use on Japanese Beetles?

[canadian-gardening]

.
I think I'm finally figuring out out to control these beetles.
Last year I saw them, but I was too late - they were everywhere.
This year I started looking for them before July and told them they had to go eat somewhere else.
Today I searched for them and I found 1 and it was on the roses.
I guess they give up on the grapevines and moved on.
Do you have Japanese beetles?
I only noticed them last year.
.

[LionGardener]

.
Hi everyone;
I still have Japanese beetles.
I'm trying a new concoction spray with: Soap, oil and water.
I saw dead beetles on my grapevines, but the new grape leaves are not looking too happy either.
So, I have to adjust the recipe.
Anyone have a recipe that works?
.

[LionGardener]

.
Second spray test on the Japanese beetles
Just

2 tbs. of dishwashing liquid soap
1 litre of water.

Why the soap-and-water spray works:
Japanese beetles don't breathe through their mouths.
Insects breathe through tiny openings along the sides of their bodies called spiracles.
So anything that plugs their breathing tubes will work.

The oil, soap, baking soda and water worked.
But it also fried the grapevine leaves.
I suppose I could cut the recipe in half, but for now it's easier and cheaper to use just soap and water.

Going to try the soap and water on other beetles and see what happens.
.

[canadian-gardening]

young-grape-leaves-sprayed.jpg

I have been fight Japanese beetles for almost 2 months.
I have slow them down, but they are still here.

Recipe:
2 tablespoons of liquid dishwashing soap
1 litre of water.
Spray bottle

Results:
Date: August 28, 2026
Plant: grapevine, including young leaves
Application: sprayed beetles and foliage
Result: beetles killed, apparently slower than previous mixture
Foliage: no visible damage so far
Evidence: dead beetles found on treated leaves
Previous mixture: killed beetles faster but damaged grape leaves

I went out today and take pictures, but most of the pictures were out of focus.
*
Let me know if you want to see more of my wild experiments.
*

japanese-beetles-before-spray.jpg

japanese-beetles-dead-after-spray.jpg

[canadian-gardening]

grapevine-recoving-august-2026.jpg

The grapevine is recovering.

[canadian-gardening]

*
September 19 and I didn't see any Japanese beetles.
Maybe they ate everything in my garden already.
Next year I will be looking for them again.

The spray:
2 tablespoons of dish soap
1 teaspoon of cooking oil or mineral oil
1 litre of water

Just Soap and Water works,
but soap, water and oil kills them faster.
I'm an impatient gardener.
*