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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?
Experiment: July 1st - First Japanese Beetle
- canadian-gardening
- Seasoned Grower

- Posts: 175
- Joined: Tue Mar 08, 2022 8:10 pm
- Grow Zone: Zone 6
- Country: Canada
- canadian-gardening
- Seasoned Grower

- Posts: 175
- Joined: Tue Mar 08, 2022 8:10 pm
- Grow Zone: Zone 6
- Country: Canada
Garden Update: July 1st - First Japanese Beetle
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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.
.
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
- Helpful Gardener

- Posts: 60
- Joined: Fri Mar 06, 2026 5:36 am
- Grow Zone: Zone 6
- Country: Canada
Question: August 11 - still have Japanese Beetles
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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?
.
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
- Helpful Gardener

- Posts: 60
- Joined: Fri Mar 06, 2026 5:36 am
- Grow Zone: Zone 6
- Country: Canada
Results: July 1st - First Japanese Beetle
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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.
.
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.
.