OT--Japanese Beetles?

Jeff Reardon

Jeff Reardon

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I know we have some gardeners on the site. Anybody got an organic solution for Japanese Beetles?

So far they are not bothering anything else, but they have exploded on my green beans--to the point that it looks like I won't get a single bean this year.

I've done the "pick them off and into soapy water" thing. Keeps the numbers down if I do it every day, but they explode again if I go away for a day or two.

A neighbor put me onto "Spinosad" last year to deal with tomato hornworms. It's great on the hornworms, and OK according to the Maine Organic Farmers and Growers, but the beetles seem to laugh at it.

Don't want to go to a broad spectrum insecticide. Any ideas?
 
What about pheromone traps? I remember them being popular in PA when I was a kid.
 
Carl, my local garden center--which sells them, and rarely does anything to discourage a purchase!--tells me they can actually be counterproductive. Seems the traps pull beetles in from a long way, and the ones that don't end up in the traps find your crops or just complete their breeding and leave larvae in your lawn for next year.
 
Absolutely I agree, DON'T put the traps out. I've never had so many as when I and my neighbor put traps out. I don't have much trouble in my garden with the Japanese Beetles but my grape vines look like lace in a few days. Personally I use Sevin but just on my grapes.

I know an exterminator in the area and asked him about them and he said to treat my lawn with barn lime. It apparently changes the PH of the soil enough that the J. Beetle grubs can't survive. I haven't tried it yet. This summer I have only had to treat my grapes once so far and they haven't come back. Maybe the drought last summer did in many of the grubs?
 
If you have them on your beans, and if you have a nice lawn, it won't be long till the crows come and start tearing up the yard to get to the larvae. Had this happen last year and it was bad - tore up 1/4 of my front lawn in a day. I put out an owl decoy on a stick and that kept the corws away - for awhile. Finally had to break down and get some larvae killer stuff I spread over the front yard. Not organic however but the only thing that kept the crows away.

And like others have said - don't bother with traps. Just brings more to the party.

Mark W
 
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What about pheromone traps? I remember them being popular in PA when I was a kid.
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No kidding Carl, seemed like my grandmother had one of the bags hanging by every rose bush she had in the yard. and they were always full.

Gene
 
Thanks for the comments.

We have the crows--and I'm happy to let them have at the beetles and other larvae. I figure grubs and beetle larvae for bird manure is a good trade.

My garden is out in a side yard that can only charitably be called "lawn". The previous owner just bush-hogged it a couple of times a year. I mow it, but only to knock the weeds down. I'm slowly moving towards a full patch of crabgrass.

The crows are doing no harm there, and staying away from the parts of the yard that have real sod.

I'm hoping that the lower number of crows this year means my beetle and hornworm struggles may be be less next year.

I think just picking them off is the way to go. I was in a muddle last night after being away for 4 days and coming home to lace instead of green beans.
 
Put up a chicken wire fence and put some chickens in there. They love bugs.

What's wrong with a little Seven Dust? Follow the label and it's totally safe. If it still bothers you, try putting in on the ground around the plants and let the bugs get contaminated as the walk across it. Only other option I know is to put mesh netting over them.
 
Kevin, As I mentioned, I use Sevin myself but you have to be careful because it is toxic to bees and we don't need fewer bees, we need more of them. I used to pick bugs off my garden plants as my old neighbor had 4-5 hives and I didn't want to harm his bees. Now that I have moved and there are no hives nearby I use it - but sparingly.
 
Kevin:

If it was a matter of saving the entire garden, I might go that route. I try to only use products that Maine Organic Farmers and Growers allow for their member's certified gardens, even though I'm not a member and don't sell my produce.

I'm told that Sevin can kill earthworms and other beneficial critters in the soil, as well as bees.
 
The best way to control Japanese beetles is to control them as grubs. But, the beetles fly so you need to treat a large area which is never prctical.

There are some 'organic' pesticides which may be useful against the beetles. Most contain either a natural pyrethrin or some type of soad. The pyrethrins can be effective, they are a plant extract. They are very toxic to many insects but, break down quickly in sunlight so there is very little residual life, your garden isn't 'toxic' for days.

Sevin dust is toxic to bees. Green beans are self-pollinating. It would be only under rare situations that honey bees would be working green beans. So, if you dust, or spray, green beans with Sevin the impact on honey bees would be minimal.

Since green beans are self-pollinating a light-weight floating row cover could be used to put a physical barrier between your beans and the beetles.

Another option could be staggered planting dates that would allow to grow before and after the beetles. Your growing season in Maine is probably short enough this isn't an option.

You could also try planting a trap crop that is more attractive to the beetles than the beans. Or, depending on the size of your garden you could plant a green manure crop of soybeans, or some other attractive cover crop.

Tom
 
For what it's worth, a customer of my (hmong) has ordered some type of small snake, said it's only three to four inches long, but loves to eat grubes and larva. cann't remember the name, but will see what I can find out.

For my family snakes in our garden and rasberries are not an option.
 
I mixed NEEM oil with water and sprayed onto our apple, cherry and maple trees and it seemed to help...
 
Thanks for the additional ideas.

I tried the pyrethrin on Sunday after hand-picking all the beetles I could find. It seemed to provide some protection through yesterday--just a single beetle on the beans last night.

A co-worker suggested Neem oil, and I'll look for that.
 
Jeff,

I have NEVER seen a Japanese Beetle here until,I put my orchard. Out of the forty tres I put in, ten were Honey Crisp, and these are "prime rib" to the beetles.

I have none on the Zestars or SnowSweet trees. The pear and blueberries ate also untouched.

I just found a product called "Surround". It is an organic deterrent made the same earth product that is used in swimming pool filter. You mix it with water and spray it on your plants/trees. It leaves a white coating that the bugs will not feed on. It will wash off in a rain, but it's organic, and is easy to apply.

Check this out.

Art
 
You may want to look into diatomaceous earth-I've had good luck with it in my garden and around the perimeter of my cabin. Just be sure it's the organic/food product brand and it's completely safe. In fact I was giving it to my lab to help prevent internal parasites. I'm just not certain about the effects on Japanese Beetles. Worth investigating.
 
As of this morning, the combination of picking once a day and pyrethrin every third day seems to have them in check. One beetle this morning, and some of my plants are recovering and have blooms. I may get some beans after all.

Thanks for all the suggestions. I may try to find some Neem oil for next year. I'm told it's longer lasting than the pyrethrin and can be used in advance to deter the initial invasion.
 
I have tripped over a natural attractant. My everbearing rasberries are next to my veg garden. The Japanese beetles are all over the rasberries & almost ignoring the vegetables completely. I can live with this because the rasberries' fall yield is my priority & the beetles will hopefully be gone by then.
 
I think that's called a 'Decoy' isn't it? In my case I don't have Japanese Beetles in my veggie garden because they are all over my grape vines. I do have a new patch of raspberries next to the grapes and they haven't been touched 'yet'. Capricious SOBs aren't they?
 
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