Something was going on with the morning glories that attracted the JB's, some kind of stress. I find JB's here only on plants under some kind of stress and often it takes quite a bit of time to find out why they are.

Jeremiahsmom,

There are many who would argue the point that plants which attract Japanese Beetles are under some kind of stress. I don't know where you live in NC but here near the northeast coast of NC we have a terrible JB population. Hence, even healthy plants get their fair share of attack. I would imagine other sections of the country would have varying degrees of JB populations and the amount of plant damage would be indicitive to those populations .

My morning glories, which were growing beautifully before the JB arrived, were also hard hit both last year and the year before. However they are a tough plant and bounced back with no problem when the voracious beasts finally went away for the season. I looked at my MG's as easy pickin's (for me picking the JB that is) and used them to put many a beetle in some soapy water.

I believe what you experienced with the beetles going after the MG's is called a "catch crop". If you do a google search you will find more information on the concept. Glad it worked for you:)

I never saw any damage on my MG's from the beetles. They were heavy on my geraniums and basil though. I didn't even grow green beans this year because they were so awful on them the year before. I still had a great bean harvest, but to have those damn things falling off the 8' towers down around me was too too much, lol.
(I just posted a list of stuff I found on the web - from someone in NC - that the beetles supposedly won't eat, you might want to check it out.)

You might try larkspur and four o clocks they attract and kill japanese beetles.

catnip, garlic, Geranium and Rue are said to repel japanese beatles.

Around here the JBs like new shoot tender plum leaves, ripe peaches, hibiscus blooms,,raspberry tips, and a few other things. I could be wrong but find it difficult to think that a hungry JB would pass up the above things even in a healthy state.

Here in Maryland they absolutely covered the Sassafras trees. I jostled one pulling some greenbriar vines at dusk and I thought I had disturbed a bee's nest the way they were swarming around it.

JBs favorite food here are my grape vine leaves, followed by roses, plum, cherry, peach, apple, raspberry, and hazelnut foliage. I find that the best time to capture them (knocking them off into a pan of soapy water) is the brief period right after sunset but before it gets too dark to see them. At that time the JBs will not fly off when distrubed. They are either too sleepy or too scared that they won't be able to find they're way back to the plant.

~ larkspur and four o clocks they attract and kill japanese beetles ~

Really? I grow both and don't have too many JBs, but I also grow a lot of other plants so maybe I'm not noticing the damage as it's spread out.

However, as I hadn't heard of this, how do these plants work? MAybe I'll plant more by my roses.

T

How then might one go about STOPPING the beetles from eating my plants?

I have found that what the JB prefer varies from yard to yard, which lends credence to the view they are attracted to stressed plants. Stressed simply means the plant is emitting a chemical signature the beetle homes in on, it doesn't mean a plant has to be at the brink of death.

Example: I hear lots of folks say they like the leaves of grape vines. I have a relative who has the largest JB infestation I have ever witnessed. He flicks literally hundreds into a bucket of soapy water daily. It doesn't help that he lives next to a golf course filled with their grubs and his neighbor has one of those yards planted with everything other than grass for them to eat.

Anyway, he has 25+ year old grape vines and the JB don't touch them.

They do go after his raspberries.

Don't touch his tomatos or any old fruit trees, do eat his dahlias.

Of course it doesn't really matter whether the JB only go after stressed plants since the JB are going to know which ones those are before we do since we can't smell the chemical signature the plant is giving off ;-)

Right now, all the Japanese Beetles are congregating on hollyhocks and agastache foeniculum - I must pick off (into soapy dish) about 75 a day. Everyday, more come and everyday I am out there like a nut holding the dish and dropping them in. They are a bit blind or stupid - because I am right in front of them and they just eat away.
Now, the bees will scatter when they see me, but the beetles just keep eating. Carrie

Good article how 2 control & prevent https://www.gardeners.com/how-to/control-japanese-beetles/5163.html

Last year they devoured my geranium. This year they've eaten the foliage and flowers of my cannas. The above posts indicate that they will eat almost anything:(