Big 'ol Japanese grubs, but a mystery too

While watering today (I flood irrigate my containers) I saw a disturbing wriggling coming to the surface as the water pooled. Dug out a very large, meaty and I’m pretty sure J.beetle grub: silvery, really big, very mobile. I see occasional lawn grubs - smaller, whiter with tan heads that I think are chafer beetle grubs, slow moving and scarce, I’ve never had a big population - but these are different. Here they are, in the suet container that they are being served to the birds in:

The biggest ones are a full inch long. I dug out all of these from an 16 inch bottomless container growing one Ichiban eggplant. Plant looks fine. I dug three times around the roots, reflooded until I saw no more and let it be. I then dug test holes around all my other containers: not a grub. Nothing except the usual small worms and pill bugs. No more larvae.

Last year this container grew a Rosemary, which was winter killed.

So…I’m puzzled. Is it possible the grubs came with the plant (its a Bonnie grown peat pot)? The other two Ichiban, bought at a much later time, have nothing in their containers.

I have only seen about 5 adults this year, all pool drowned. Much, much fewer adults here than usual. I’m hoping this is a very localized issue. I hate to lose the plant, but I’m considering putting screen along the soil level to block any larva that I miss pupating into adults and leaving. And of course I will pitch it if I have to.

Weird. Thoughts?

There they are: agents of Satan.

Folks, go out and get some Milky Spore. Now is the best time of year to apply it on your property for maximum effect. It will KILL these bugs while they are in their grub stage.

Get Milky Spore powder. Drop a plastic tablespoon’s worth on the ground. Walk four feet away, and drop another spoon’s worth. Proceed another four feet… drop. Do this in a grid-like fashion across your property. Apply before, during, or just after rain for maximum results. It is non-toxic and will kill nothing else but Japanese Beetle grubs. Just don’t breathe in the powder. Best investment you’ll ever make.

Matt you’ve got it right. We put down milky spore for three years in a row and we haven’t had a Japanese beetles here in years!

1 Like

Thanks Matt. I’ve never seen the need for it but I think I am going to go ahead and get it onboard now. I like being in the right window to get it down.

Godawful ugly things, unless you are a bird.

Excellent, Mrs G! whoosh! off to order

Man, you think you got a bad infestation, lol!

Its so weird, TNG! I’ve never had J. beetle grubs in any size and then to have them in just one veggie container…bizarre. I dug about 100 test holes, lifted new container plants, lifted lawn up here and there. Not a thing to concern me. Just this one spot…

But, I am now an acolyte of the Milky Spore Faith, having read up on it more (thanks Matt and Mrs. G!) We need someone practical in the Oval Office to make this stuff get put down everywhere. One invader at least would be wiped out!

My MS should be here tomorrow or Monday.I found about 15 brown (chafer?) beetles in the pool filter - still no more Japanese adults.

1 Like

Milky Spore has not worked here at all. I can’t do my neighbor’s lawn, so it’s pretty useless. After 3 years of using they are worse than ever. I feel I wasted quite a bit of money on the product. I’m using BT for Japanese beetles this year.

There’s the rub, isn’t it? I’m going to get it down and see if I get results. I’m still shaken that I found so many of them.

How do you find BT working, Drew? That’s safe on veggies?

The birds, BTW, enjoyed those grubs immensely.

Yes, it’s safe. I have not had to use it yet. The Japanese beetles are just maturing here. i only found one adult, so waiting a bit to spray. The Milky Spore does work, but I have the surrounding area untreated. i suppose with time the bacteria might make it around farther. With the BT any beetles that feed die. That is a better approach for me.

Well then adding BT is like another layer to the control approach. It may help in suburban circumstances like ours where neighboring lots may or may not be treated and adults overlap.

I’m lucky, my neighbors on both sides treat. Across the street, no.

Yeah. That’s what Integrated Pest Management (IPM) is - using mulit-pronged approaches.

Since they can fly, the suckers will eventually find you, even if everyone on the block treated. The more adults that are killed, the fewer eggs they can lay. The more grubs that are killed, the fewer adults in the area the next year. The fewer attackers of any kind on the plants, the stronger the plants can grow. The stronger the plants, the more able they are to withstand future pressures.

Since they pierce the leaves, JB’s are probably vectors for some kinds of infections. Even if they aren’t, the amount of defoliation they can do weakens their victims and makes them more susceptible to other stresses and infections, which may spread to other plants.

Probably the better sucking, chomping insects are controlled, the healthier and more productive the plants in the area can be.

Go get 'em!

1 Like

Well said Muddy! And that’s a great point about them being potential disease reservoirs or vectors, like ticks or skeeters are to us.

I’m so on board to banish them as much as possible. Funny because I remember them as terrible infestations here when I was a kid, when we lived further out on the east end of LI. Wonder if its all the farmland and sod farms out there…probably.

I checked the veggie container I saw the grubs in (still the only spot). Looks like I got them all in there anyways.