A good question for my Organic friends

[MysticGardener67]

In my region, japaneese beetles are a very big problem, most years.

We have been backhandedly fortunate past two seasons because late spring freezes have been catching the grubs close to the soil surface and killing them off.

I have used beetle traps, but have learned that the only good way to use them is to place them in somone elses garden, drawing the pests away from MY garden. The neighbor was not very enthused about this tactic. I also used to be a fan of sevin/carbaryl, but I have stiopped using it because it is teribly detrimental to beneficial insects and the native fish stock.

I have come up with a more organic strategy, but I want to hear other ideas to see if I am on something new.

[MysticGardener67]

I wan't paying attention when I posted this, should have gone into the insect sub forum. Was sorting out issues amongst my boys. Kinda got REALLY distracted! Forgive???

[The Helpful Gardener]

All good, Mystic (you should visit our Connecticut town of the same name when you get the chance)...

[url=https://pubs.acs.org/doi/abs/10.1021/es0516965]Carbaryl[/url] is not very good for YOU, let alone insects and fish. Twitches, muscle loss, blurred vision; long term effects are still under investigation, but url=https://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC35377]carbamates[/url] are bad guys, a [url=https://www.pesticideinfo.org/Docs/ref_toxicity6.html#CholinesteraseInhibitors]cholinesterase inhibitor[/url] (which show likely ties to Parkinson's). Bad. And did you catch the part about how kids are more susceptible?

BAD.

Nematodes are an excellent tool for controlling beetles, especially when you get them at the larval (grub) stage, still in the soil. When things start eating BT can be an excellent deterrent, but you must get the beetle killin' form (Bacillus thuringiensis var. san diego or Bacillus thuringiensis var. tenebrionis). These are poisonous ONLY to beetles that eat the treated plant; no chance of going off target here.

That's GOOD. Really good...

HG

[MysticGardener67]

Several years back, the gardencenter I was working at was suffering a Jap Beetle invasion. I observed. What I noticed was that they were preferring certan plants over others. What they LOVED were porcelain berry Vine (Ampelopsis glandulosa brevipedunculate ). "Hmmm.."' I thought, "That's interesting." Then I noticed in my garden that they gladly munched on our concord grape vines, preffering them to my rose bushes. again.."Hmmmm.."

Has any other other helpful gardeners noticed similar preferences with either Jap Beetles or other pests?

[applestar]

Grape vines definitely -- I had a volunteer wild grape vine that I decided to let grow on an arch trellis. Ultimately, it wasn't in a good place after all. As it turned out, the cheap Craft Store trellis was unable to support the HUGE mass (it grew like crazy in just one season) and collapsed on its own, so the "design" was abandoned. But BEFORE that happened, the Japanese beetles descended on those grape leaves. I was out there every morning with a plastic grocery bag knocking about 30 beetles into the bag to dispose of. I did get a nice bunch of grape vines to make wreaths with for the holidays out of that though.

In the autumn I treated about 15~20 ft radius around the ill-fated trellis with Milky Spore, and I didn't get an explosion of beetles next summer as I feared. However, I have a vague recollection that someone on the forum said Milky Spore is not entirely environmentally friendly and shouldn't be the first choice in Japanese Beetle control.

Other plants that I've noticed the JAPANESE beetles seem to favor are JAPANESE vegetable crops like Shiso and Edamame, as well as ornamental JAPANESE Cherry and JAPANESE Maple leaves. I guess like any displaced ethnic transplants, they favor their most familiar heritage culinary experience.

Unfortunately, they've adapted to American cuisine and also do like native plants like Evening Primrose. They also seem to like the Lady's Thumbprint-like wildflower/weed (There are two kinds, one is a Pennsylvania native -- I've yet to properly ID the ones in my garden, though I do know similar plants grow in Japan, commonly called Aka Manma (Red Rice). My mom says the ones in my garden grow too tall to be the Japanese kind....) and on the Nectarine leaves but not Peach.

[The Helpful Gardener]

Hibiscus, regardless of species seems a sure fire draw. Maybe not so much Rose of Sharon (H. syriacus), but the perennial variety native around here (H. moscheutos and like species) and the tropical species (often H. rosa-sinensis, but there are [url=https://en.wikipedia.org/wiki/Hibiscus]LOTS of species[/url].

And roses and grapes for sure...

HG