Japanese beetles in the garden, arrrr

[Meatburner]

Good morning all. How do you fellow gardeners deal with Japanese beetle in your garden? They have invaded my green beans and are munching away. Thanks for any advise.

[rainbowgardener]

First thing is not to panic. They only stay in their adult form for 4-6 weeks, then they lay their eggs in the soil and go off and die.

If you come out early in the AM while it is still cool, they are slower. You can put a bowl with soapy water under the stem where you spot one. If you shake the stem/branch, the beetle will fall off, right down into the soapy water. They can swim around for awhile, but if the bowl is big and slick, they can't climb out and eventually drown.

Won't help for right now, but in the fall you can treat your lawn and garden with milky spore disease and/or beneficial nematodes. That will kill the grubs/larvae, so you will have fewer JB's next year (probably not none, because they are strong fliers). Wild grape vine is a good trap crop for them, especially when it blooms. They will just stay on the grape vine and not bother your crops. If you want to, you can catch them from where they are congregating on the grape vine.

Neem oil sprayed on your plant leaves should work against them. It isn't a poison and it doesn't kill on contact. It will take a few days to see the results.

[imafan26]

They are very difficult to control. You can control the grubs in your lawn with a turf grub control insecticide. Beetles can still fly in from neighoboring yards so unless your neighbors also treat their yards, it may not help in the long run. According to the Minnesota article organic methods don't work very well. Milky spore did not work well on grubs. Timing of the the soil treatment is important since the grubs are only susceptible betweeen mid July-September. Beneficial nematodes may be helpful if you can get them.

Hand picking the adults and soapy water is what is recommended for light infestations. Most organic insecticides won't work well and you would have to use something with residual effects which will be more toxic to bees, birds, and/or fish to control large infestations. Companion planting apparently is of little help as the beetles give off pheromones that attract even more beetles.

Japanese beetle traps work but also attract more beetles than it catches. They would work better for you in your neighbors yard so the beetles would go there instead. The article said the lure is very powerful and works better if there is a bowl of soapy water with a white bottom is placed under it. The lure catches other beetles but the floral lure also attracts bees so the trap should not be removed early in the morning before the bees forage and put out just after sunset.

I do use the floral lure to kill Chinese rose beetles which does similar damage, but I place the trap on the opposite side of the yard from the target plants. I haven't had to use the trap in years since I can interrupt these beetles feeding cycle by planting my roses under a light and I have a lot of skinks, and anoles that like to eat beetles and grubs.

Actually, if you had a chicken, they do a good job of keeping the slugs and insects under control. It is just that they also like to eat your lettuce, seeds, and seedlings so you do have to keep and eye on them.

https://www.extension.umn.edu/garden/in ... e-beetles/

[applestar]

There are wasp Garden Patrols that help, too. narrow waisted solitary wasps, tiphiid wasps, and long tail/ovipositor ichneumon wasps.

This link is a list for Kentucky, but I've seen some of them in my garden
Narrow-Waisted Solitary Wasps of Kentucky - University of Kentucky Entomology
https://www.uky.edu/Ag/CritterFiles/case ... litary.htm