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NewRiverGeorge
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Japanese Beetles, how I loathe thee

Wow just wow,

How destructive are these guys? I had to work a few late days and before I even knew I had a visit from these demons, the damage was done. These guys think my garden is a 24/7 Salad Bar. I have always tried to avoid any type of pesticides, but I applied Sevin 2 days ago and it seems to have done the trick. Anyone else had any experiences with these nuisances?

NRG

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applestar
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Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)

:| Sevin, really?

Well, you are not going to like my solution, I suppose -- I used milky spore to kill the grubs in the past, but got to wondering if the bacteria might infect desirable beetle grubs as well. So then I considered and used predatory nematodes but had the same dilemma after discovering firefly pupae in my garden soil. I resorted to bagging the plants, cutting off the plant/branch or just shaking as much of the JB's as possible from sturdy branches and plants, then thoroughly stomping on the tied closed bag from the outside. :twisted:

Fast forward to a couple of years ago, Japanese beetles descended in biblical proportions, and EVERYTHING was being munched. Cherry tree leaves, hazel bush, and I happened to be growing lots and lots of pole beans and runner beans -- all turned into lace.

But then I realized I was still getting plenty to harvest. So, I decided to wait for the natural balance -- at that point I reasoned there should be sufficient JB population to attract their natural predators... only problem was they are not native species. I researched and found out there should be a released population of JB parasites in this area, and I had the necessary nectar/pollen attractant -- blooming carrots. In the mean time, I started finding beheaded JB's and empty bodies/wings, so other predators were getting them, too.

There have been a lot less JB's since that year. Hoping the trend will continue. :wink:

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rainbowgardener
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First thing is not to panic. (Although it is too late for that, you already panicked and sprayed poison all over everything.) 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. Personally when I had a lot of wild grape growing, I didn't even bother trying to kill the JB's. They weren't bothering my other plants very much and the wild grape is a hardy weed that they couldn't destroy.

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

Here's some info about your Sevin, which is banned in the United Kingdom, Denmark, Australia, Germany, Sweden, Iran, Angola, and other places:

SEVIN (carbaryl)

Product names: include Carbamine, Denapon, Dicarbam, Hexavin, Karbaspray, Nac, Ravyon, Septene, Sevin, Tercyl, Tricarnam, and Union Carbide 7744.

Class and uses: Carbaryl is a wide-spectrum carbamate insecticide which controls over 100 species of insects on citrus, fruit, cotton, trees, and other crops, as well as on poultry, livestock and pets. It is also used as a molluscicide and an acaricide (against ticks and mites). It is a neurotoxin.

Human toxicity: Carbaryl can produce adverse effects in humans by skin contact, inhalation or ingestion. Most of these are minor for one time exposure and can only happen if you get it on your skin, swallow some, or breathe it in. Chronic exposure to Carbaryl, as in agricultural workers can cause cancer and many other problems.

Animal toxicity: Carbaryl is acutely toxic to fish. Carbaryl is acutely toxic to birds, although the dose required to kill most species is greater than that required to kill mammals, fish or insects. Carbaryl also adversely affects birds at lower doses by reducing the population of insects and aquatic invertebrates that the birds feed on. Unhatched and young birds appear to be particularly sensitive to carbaryl exposure. Earthworms are sensitive to small amounts of carbaryl in soil. In field studies, carbaryl treatment reduced earthworm populations by between 50 and 90 percent. Follow-up studies showed that populations took five to twelve months to recover and that the rate at which mineral soil was incorporated into thatch was significantly impaired during this period. It is toxic to frogs, shrimp, crabs, clams, snails, some aquatic insects, and many pond living creatures. Carbaryl is highly toxic to honey bees, certain beneficial insects such as lady beetles, and parasitic wasps and bees.

Plants: While insecticides are not usually assumed to have adverse effects on plants, carbaryl's use as a plant growth regulator (chemical thinning agent) makes effects on other plants unsurprising. It has been shown to decrease germination success, inhibit seedling growth, reduce photosynthesis, and reduce nitrogen fixation. Note that several different people have written in to helpfulgardener to say that their gardens died after being sprayed with Sevin.

Fate in the environment: Because of its chemical characteristics, the U.S. Environmental Protection Agency (EPA) identified carbaryl as one of the pesticides with most potential to leach into groundwater. It has been found in groundwater in California, Missouri, New York, Rhode Island, Virginia, and Wisconsin. Carbaryl was the most commonly detected carbamate insecticide in the 1991 U.S. Food and Drug Administration pesticide residue monitoring program; it was the tenth most commonly detected pesticide. It was also one of eight pesticides detected in baby food samples

References: https://www.healthyworld.org/sevin.html
https://www.dontspraycalifornia.org/carbarylog.htm
https://pmep.cce.cornell.edu/profiles/ex ... l-ext.html
https://www.pesticideinfo.org/Detail_Che ... Id=PC32816

So note that you have probably killed every insect on your property including the beneficial ones. If birds eat the insect corpses they will be at least harmed, possibly killed. The consequence of killing off all the beneficial insects is that you are likely to experience a rebound of pest insects. Not necessarily the JB's, because their adult life span is so short (hardly worth bothering about!), and their reproduction so slow. But lots of other things, aphids, thrips, stinkbugs, whatever kind of insect pests you have around. Just like wolves and mice, the prey population is much more numerous and much more rapidly reproducing. So the prey/ pest population will come swarming back and find no controls for them.

People get addicted to poisons that way, thinking now that they are having an explosion of pest insects, they have to spray more poison. Please don't. It is a sign that you have put your garden all out of balance and need to work on putting it back in balance.

imafan26
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Glad I don't have those. I have Chinese rose beetles, but luckily the lizards and birds like to eat them and planting roses near the street lights keeps the roses relatively hole free and I don't really do anything about them. I did use a japanese beetle trap for them in the past and I got a lot of them. I only use the floral lure. I did have to take the lure out every morning or the bees would end up in it too. The Japanese beetle traps are not recommended but I found them useful. I just put them in the farthest corner that was away from the plants I wanted to protect.

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rainbowgardener
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Oh and re your question: "Anyone else had any experiences with these nuisances?"

Pretty much EVERYONE east of the Mississippi has had experience with them. Apparently they don't have them in the western half of the US

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pinksand
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A co-worker mentioned he's had great success with Japanese beetle trap bags called "Bag a Bug." I've never used them personally, just hand picked the beetles and squashed them... which does take forever.



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