Wow, my gardens are really taking a hit this season, with spring sickness, leaf streak, aphids, and now Leaf Miners!
I started to wonder about the Miners when I started seeing leaves like this:




But today, as I was foliar feeding, I saw this little guy:









Am I correct in assuming that these are, indeed, Leaf Miners? I didin't know they could be this far north, but then again, I have dozens of newly arrived plants from southern sellers.
If these are Miners, will they overwinter here? Will I need systemic pest control?

My plants are looking so bad, and it's making me so sad, that I'm about to give up on my daylilies.

Yes they are recorded from Ohio. I believe they will overwinter there, it's not exclusive to southern areas. A lot of people just remove and destroy the mined leaves, it depends on your level of tolerance. Further info from the AHS here:

https://www.daylilies.org/ahs_...

sooby said:Yes they are recorded from Ohio. I believe they will overwinter there, it's not exclusive to southern areas. A lot of people just remove and destroy the mined leaves, it depends on your level of tolerance. Further info from the AHS here:

https://www.daylilies.org/ahs_...

Thank you for replying, it's appreciated. I read that link, but while it said that contact insecticides wouldn't work, it didn't mention systemics.

I'm about to cut back my plants and use a soap wash for aphids, do you think that would make any difference at all?
I'm also thinking, based on those photos above, that I need more spiders in my gardens.

@mystlw
What a beautiful photo. I want those spiders in my garden...lots of those.
I don't think a soap wash will do a thing to deter leaf miners.
I was just reading about using sticky traps for them, I am considering making my own. Pulling leaves might be an option when they are only a few damaged, but in my garden that would be too large of a task. I often see it recommended to pull leaves, for leaf miners, to pull leaves for leaf streak and for rust. So as I've said before that would leave no leaves on the plants here.
I deal with all those problems here, and as depressing and challenging as it is, it is the critter damage that really gets to me.

Seedfork said:@mystlw
What a beautiful photo. I want those spiders in my garden...lots of those.

The interesting thing is, I've also been seeing frequent hornets in my beds, which is something I've never seen before; it makes sense now that they might be after the Leaf Miners.

Seedfork said:I was just reading about using sticky traps for them, I am considering making my own. Pulling leaves might be an option when they are only a few damaged, but in my garden that would be too large of a task. I often see it recommended to pull leaves, for leaf miners, to pull leaves for leaf streak and for rust. So as I've said before that would leave no leaves on the plants here.

Do you have a link to instructions for making your own? Would it be similar to hanging those sticky fly strips on stakes? (I'm wondering if it could be as easy as that.) I'm in the same situation here, if I start pulling leaves I'll end up with empty crowns. And I have a lot of plants that are newly arrived and potted, which are still dying back.

Seedfork said:I deal with all those problems here, and as depressing and challenging as it is, it is the critter damage that really gets to me.

My daylilies are a great source of comfort for me; I'm finding all of these challenges at once somewhat difficult to cope with. I don't like to see them struggling.

I once tried sticky traps in the vegetable garden. A poor little bird got stuck on one. I tried to catch it but its wing was stuck fast. It scrambled away into a hedge and I couldn't save it. Presumably it eventually died. So I've never done that again, strictly indoors only. Maybe there's a way to enclose them in something that would just let the insects through.

What I was trying to say above is that whether you try a systemic insecticide depends on how bad the infestation is and your tolerance for it. In some cases there are only a few leaves affected so you can remove and destroy them to reduce the number of miners. Growers may decide to just live with it. When a leaf is still mostly green it is still functioning (photosynthesizing) even though we might not like the look of the wiggly lines.

Using a systemic insecticide can have an impact on other, possibly beneficial, insects as well so it's a personal judgement call whether one decides to go that route. Well, it wouldn't be where I am because systemic insectides are banned for homeowner/cosmetic use by the provincial government so unobtainable anyway, but fortunately the leafminer hasn't found its way here yet.

mystlw
No it is not as simple as that, the sticky traps (blue) I think for leaf miner is only a partial step.

I did read that Spinosad could be used for the treatment of leaf miner. I actually bought some, and forgot till now what I bought it for.
I also read that neem oil could be used, but I personally have had no luck with neem oil for anything.
Edit:
Forgot to answer your question about making your own. I read to use blue plastic plates or cups and to cover them with vaseline and hang them by the plants. So you can see that would not look very good if you have over two hundred named varieties, many NOIDs and hundreds of seedlings. But I don't know how much area would be covered by a single trap. I might try that on a small area. And of course vaseline on a plate or cup would not trap any birds. It does not have to perform up to mouse catching standards just sticky enough for small insects. Of course they would have to be monitored and replaced fairly often, but then they would also be cheap.

For neem oil to be systemic I believe it has to be used as a soil drench. Whether it works for daylily leafminer I don't know. Some people have used imidacloprid for daylily leafminer, but that systemic insecticide (a neonicotinoid) is under scrutiny for being harmful to bees.

The neem oil is just sprayed on the plants and is supposed to suffocate the pest. It is not used as a systemic.

mystlw,
Here I found a lot of info on the leaf miner.

Sooby,
The leafminer was discovered in Florida in 2011(I am sure you already knew that) but that leads me to believe it would probably arrived here maybe a couple of years later. Not sure how fast and far that fly can travel. The plants that were infested with them might have traveled even faster.
Edited:
I read the leafminer was first discover in Florida in 2011, but that was the first in Florida, not the U.S.

The daylily leafminer was first noticed in North American around 2006 in Maine. If you look at the daylily dictionary entry I posted above, you can see how many states had it by 2014. See:

https://bugguide.net/node/view...

Larry, Google with the keywords neem oil systemic soil drench. I don't think I would try it without testing on a plant or two first that way. It may be the the neem derivative, azadirachtin, works better. I haven't looked into it that much recently.

Edited to add - here's one study on neem for a different leafminer, although note they used the neem extract azadirachtin (which you can also buy in various products) as a soil drench compared to leaf dipping:

"The systemic effects from a soil drench had a greater adverse effect on pupation and adult eclosion than leaf dipping."

https://www.researchgate.net/p...

Yes, I just found that info.
http://docplayer.net/76175553-...
It says the leafminer was actually in Alabama in 2010.

I've got the little buggers here in Nebraska. Noticed the other day after reading another recent post about pests and leaf problems... Not on many plants yet, so I'm removing leaves. I do have a decent spider population and I saw a wasp or two in the beds today. And tons of fireflies are finally showing up. Apparently, firefly larvae eat lots of other bugs, hopefully the undesirable ones!

I never thought about what a firefly eats, but I just read that the larvae are predatory and eat a lot of snail and slug larvae. I have a much greater appreciation now for the firefly larvae. However, as an adult I see that they eat pollen and nectar.

True, and I think it's a fair trade. We have to beat the bees to the pollen too..

Whatever they eat they light up our lives!

ShakespearesGarden said: I do have a decent spider population and I saw a wasp or two in the beds today. And tons of fireflies are finally showing up. Apparently, firefly larvae eat lots of other bugs, hopefully the undesirable ones!

Thanks for this! I HAVE been seeing a ton of baby fireflies on my plants, but didn't know if they were beneficial or detrimental. I didn't kill them, though, because...well, they're fireflies!

I got my leafminers from Missouri about 4 years ago.

It was a fall order, and while cleaning the plants for planting I found some pupae inside the leaf bases.

I think if you're going to strip leaves in order to control leafminer, it might be best done in the late fall, after the larvae have pupated for the winter, the dormants are resting, and the evergreens and semi's aren't going to be too affected by leaf loss. It would be a good opportunity to freshen up the garden. The pupae I saw were inside the leaves, at their base, close to the crowns.

@CaliFlowers
What do they look like, Ken?

@touchofsky
https://www.daylilies.org/ahs_...

The pupa looks exactly like Figure 4.