Sweet Corn
Japanese beetles, along with a lot of other other natural disasters, are making the garden a little less fun this year. The beetles have only been in Wisconsin for about a dozen years, and they are loving it here. Their populations seemed to diminish for a few years, but this is the worst infestation I’ve had. They’ve not bothered the sweet corn before, but this year they are destroying some silks.
Japanese Beetle Collector
Most years I can keep up with them by just collecting them with this trap. But this year there are just too many. Some of the damage is significant and hurting production. I just tried a hot pepper spray. We’ll see what happens with that.
Okra
Raspberry
Elderberry
Blackberry
Sweet Potatoes Under Wraps
My sweet potatoes were getting double hammered. Japanese beetles and deer. The fabric deters both.
I’ll be happy to entertain any good, organic, ideas on Japanese beetle control.
We don’t seems to have the little buggers but when we did, I sprayed them heavily with hot soapy water. The soap closes their pores and they can’t breathe.
I’m a newcomer to southern Wisconsin and only there part time. I noticed quite a few beetles in my plants. I wonder what would happen if you mashed or blended the dead ones with water,strained and made a spray to spray on plants.
I set up 5 five gallon buckets with 2″ PVC tubes two feet long through a 2 ” hole drilled into the lid. On the top of the tubes are 3″ reducers to the 2″ tubes. An X form of plastic holds a tangle foot Japanese beetle scent attractant, The beetles are attracted to the scent bock and when they land on the plastic the slide off the slick plastic and down the tube to the bucket and they can not get out. I have trapped about 25 gallons of them this year. Horrible devils.
they haven’t touched my sweet potatoes yet, but are amorous on the raspberries. Pickin off one by two.
Have you tried milky spore? It’s a fungus in the soil that goes after the grubs. You apply it twice and then it stays in the soil for up to 20 years. Not 100% effective but drastically reduces the population. Should be able to get it at any good garden center.
Years ago, in the 1970’s, when we were having a bad Japanese beetle year here in Massachusetts, I sowed the Bt (Bacillus thuringiensis japonensis (BTJ)) into my lawn. While it didn’t work immediately (it works on the grubs, not the adults), the beetles declined precipitously over the next few of years. I can’t remember when I saw even one beetle in the past ten years.
This link gives a good rundown of various biological grub controls.
https://www.thoughtco.com/how-to-control-japanese-beetles-1968381
Fortunately it is much easier to buy these controls now with the Internet that in the old days.
I hope this is helpful for you.
Two Midwest weeds are very attractive to Beetles. Velvet leaf button weed provides a large flat surface for females to attract males for mating. Pennsylvania smart weed is popular with the beetles as a food source.
Plant them about 5 feet beyond your sensitive plants from seed in late May and they will be ready to host the beetles in July.Keep the plants out of productive beds.
Go out with buckets of soapy water just after dawn and collect the beetles by shaking smart weed and brushing them off buttonweed into the buckets. This kills them. After mating, the males die and fall to the ground, if not caught in the buckets. Dump the soapy beetle buckets into a toilet and flush them to your septic tank. You will kill them and the females will not have had time to lay their eggs.
milky spores – takes a while for them to be super effective. Put them down 5 years ago, saw improvement each year but this year is the best. I have been gardening for over 50 years and have never found an organic spray that works.
I’ve read conflicting information on whether dead beetles attract more beetles. Live ones certainly do, once you get one, they cluster. Also, I wouldn’t want to work with a mess of ground up beetles, they really do stink.
I just tried a hot pepper spray and that initially seems very effective.
This sounds quite interesting.
I haven’t tried Milky spore or Bt, yet, because this was the first year I couldn’t control them by hand picking. I just tried a hot pepper spray and while it’s too soon to say for sure, it appears to be quite effective in repelling the beetles.
Thanks for the comment. I may try Bt for future control.
Thanks for the comment. I hand collect a lot of beetles with the funnel collector I have pictured in the post. My best trap plant is Russian comfrey, which is just on the edge of the garden. The beetles are preferring that to almost all the other plants close by.
I’m considering milky spore or Bt going forward. However, I appear to be having some luck with a hot pepper spray. I have a neighbor who swears by it for beetle control.
Be careful with Bt, Bacillus thuringiensis. It will kill all caterpillar larvae, including monarchs. I use NEEM spray, an organic insect deterrent for the Japanese beetles. However, it also seems to deter the pollinators. What can we all do? Hand pick them off small gardens and put them in soapy water. If you crush them, the scent attracts more. They are definitely having a population explosion this year.