Flea Beetle Larvae on Leaves

[sunflowerdane]

hey guys , i seem to have some flea beetle larvae on my leaves near my hollyhocks. they arent bothering my veggies , just my flowers.
ggrrrrrr what do i do? and why do i have them?

[The Helpful Gardener]

Flea beetles are not picky about food source, are quick, with pretty decent armor and they are hard to spot. Surprised everyone doesn't have them; I have been fighting them on the potatoes, mostly, but even my Jack Frost brunnera got a shotgun blast of holes from these little buggers...

I use pyrethrins, neem and insecticidal soap (alternated) for local control, and hope to get nematodes on them in July/ August when they are laying next years crop of grubs in the soil (nematodes are a great way to break the cycle and get them out of the garden for a while; wipes out the next generation). I suggest a formulation of both Steinernema carpocapsae and Heterorhabditis bacteriophora; the folks at North Country Organicsare the only ones I know mixing them for you...

Really like that company... Smart products from smart people...

HG

[sunflowerdane]

thank you so much
will do!

[The Helpful Gardener]

And the number one reason flea beetles show up in a garden is that they never left; cleaning up the plant debris at the end of season is imperative with these critters...

HG

[wolfie]

Hey Scott, I just read thru that North Country website for the Grub Guard, my question is how do I apply it, I don't understand the websites application? Also, this kills those white grub things that turn into japanese beetles right?

thanks!

[The Helpful Gardener]

Hey Wolfie...

Any grub in the ground we basically lump together as "white grub complex"; you can tell them apart if you want to measure them and count the hairs on theitr butts (no, not a wierd colloquillism, prone as I am; the hairs or raster patterns on the butts of grubsis the best ID key). But with nematodes it doesn't matter... they like them ALL...

It will come with directions but it's pretty simple. You are treating the soil the grubs live in. The best time of year to treat is pretty quickly; you want to get in the soil as the adult beetles are laying or just after to get best results. Nematodes predate across the whole WGC, and propagater themselves in host bodies, so only treat where you have issues. Blanket treatments are only nominally effective; they will follow the "plume" from wherever the big hatch happened seeking food, so not to worry about coverage. Order early in the week; a weekend stuck in a post office has killed more nematodes than I care to think about. UV rays are another bigg killer; apply on rainy days or at dusk; watering afterwards is also helpful. I have always used watering cans, both at home and professionally, but find the clay suspensions clog roses, so leave the rose off.

Done correctly nematodes are an excellent curative and preventative; I did my frontlawn dutring a really nasty grub outbreak three years back and still haven't seen enough to warrant treatment. Let's be clear here; I still see grubs if I cut a square foot of turf, but maybe one or two, and no obvious damage. Because of the nature of organic lawn, my roots are going down 12-14 inches at this point (CAN'T do that with chemicals), so if they nibble a bit at the bottom, no big deal...

I hit my flea beetles early this year with both barrels (pyrethrins AND neem in rotation) and haven't seen any in a while, Squash beetle and striped cucumber beetle were coming on, but assasin bugs have showed up and wrecked their fun. Saw more assassin bugs than beetles tonight on the twilight tour ...

Picking zukes and summer squash and wax beans

HG

[wolfie]

Thanks Scott for the info. I guess my next question is how do I tell if there is an outbreak in any one area? I have not seen a whole bunch, I do know that when I had laid bags of top soil on the grass while I was waiting to fill in my beds, when I lifted a bag up I would see 4-5 grubs go into the ground quickly, but other than that, I have no idea where they are. Any good ways of telling? Thanks!

[The Helpful Gardener]

Shan, grubs don't do much quickly. Sure they weren't worms?

For lawns, I cut a one foot by one foot turf and pull it up. If there isn't ten or more grubs, it's all good (generally). Actually knowing what grubs you are looking at can help (why I included the charts in that previous link) as some can be more destructive (for instance black ataenius is a smaller beetle but very destructive, and four of them might make me nervous, but I have only seen it in a home lawn once and it was not far from a number of golf courses. And see what they recommended in the link for treatment? Can I get an amen? ) ANfd they are saying forty per sq. ft. before treating? Not after what I've seen them do to a lawn....

Nematodes DO NOT predate on earthworms, so it's all good, but if you don't provide food sourcing (WGC), they go hungry and move or die, and you just spent good money for nothing. So it is just like any other evil doin' perp, make sure you have a good ID before you start shooting!

HG

[wolfie]

well i am pretty sure it was a grub, but i didnt see the hairs so can't be sure what kind lol

i can cut up some lawn and see if anything is in there before i buy tht stuff, as I agree, i don't want to waste money on chasing a grub lol

thanks for your help!

[hendi_alex]

In my garden the flea beetles seem to just love the egg plants. I inspect the egg plants each day and squish a good number of the beetles. My point is that the beetles seem to be enjoying the egg plants and virtually ignoring EVERYTHING ELSE. So why not try planting a few egg plants as trap plants, and wage your war there.

[The Helpful Gardener]

I can second that experience Alex; they do seem singularly drawn to that particular crop. S'why I didn'y grow it this year, but they showed up on taters, and even did a number on my Looking Glass Brunnera; looks like it was shot with a twelve gauge!

HG