probably slugs.. or any of the leaf chewers.. that chew in the middle of a leaf ..

ken

Moccassin,

Have you seen any caterpillars or other insects around it? Sounds like "rose slugs" or sawfly damage. Have you seen this on Rose foliage before? Link below.

Steve

Here is a link that might be useful: Rose Sawfly damage to leaves

Regular slugs seem on the wane with all the Sluggo and stuff I've used, and the copper necklace around some of the hosta.

But Steve, I've seen lots of the sawflies and wondered what they were doing. So they were laying eggs which have hatched out? And will a treatment of the ammonia/water 1:10 work with these things as well?

Criminy, I wondered what those things were!! Swarming like fruit flies.

You probably need to spray a little insecticide once every few weeks on your hostas to catch more of the bad insects. You could also use a Bayer Advanced Insect Killer spray which has Merit in it, is systemic, and kills nematodes. Spray it into the leaves down to the crowns.

I also saw someone is eating leaves already with only 5 % leafing out in my garden, gave them some Bug Geta pellets.
Bernd

OK, Bernd. My DH is headed to Lowes in the morning, I'll put this on his MUST HAVE list.

I'll look it up now, and put it at the top of his list.

I found BAYER ADVANCED GARDEN ROSE & FLOWER INSECT KILLER in spray bottles, containing the systemic Merit. Says to use in the shade, let dry. Spray soil and the plant down to the crown, if used indoors ventilate, keep away from pets and kids until dry, avoid breathing it in. That Merit is the same stuff in Advantage flea and tick application for dogs. One spray bottle of the Bayer formula is said to do 35 plants--but it did not say what size plants.

Going to get three bottles.

Thanks Bernd.

OK, Bernd. My DH is headed to Lowes in the morning, I'll put this on his MUST HAVE list.

I'll look it up now, and put it at the top of his list.

I found BAYER ADVANCED GARDEN ROSE & FLOWER INSECT KILLER in spray bottles, containing the systemic Merit. Says to use in the shade, let dry. Spray soil and the plant down to the crown, if used indoors ventilate, keep away from pets and kids until dry, avoid breathing it in. That Merit is the same stuff in Advantage flea and tick application for dogs. One spray bottle of the Bayer formula is said to do 35 plants--but it did not say what size plants.

Going to get three bottles.

Thanks Bernd.

I may have to try that too, and soon, before the earwigs begin to make lace out of my heuchera and hostas.

Karen

Moccassin,

Just follow the label directions carefully. Imidocloprid kills bees, so use it after they have gone to bed.

Steve

Moccassin,

Just follow the label directions carefully. Imidocloprid kills bees, so use it after they have gone to bed.

Steve

Moccasin, I did not see that Bayer Rose & Flower spray, only in granular form. The Bayer Tree & Shrub Protect & Feed has much more % of Merit than the Rose one has, found it only granular, so I bought 2 bottles of the Tree one and applied already one. Most of my hostas are still only pips, but the soil needs to be drenched already in that stage, I only have pellets. It is the same with fertilizer, to give them a good start use liquid fertilizer. Granular time release fertilizers seem to provide most of the nutrients relatively late, such as when hostas get dormant in summer.
Bernd

I have seen similar damage done on my citrus trees' new growth (chewing in but not THROUGH the leaves) by "leaf miners" -- though it was typically in a wiggling pattern as they bore through a layer of the leaf.

Yikes, that also looks like Nematode damage. Check for insects on the foliage in daylight and dark. Any insect should be visable especially at night. If none are found do consider the possibility it could be nematodes and if so throw it out as there is currently no known cure that is effective.

Scott

Don't let Ken hear you say that, Scott. Nems are only visible in the summer. I hope his butt doesn't explode.

Steve

Protecting Ken's butt here, after his bedtime...but I think he can do that for himself very effectively. Nematodes don't look like that on hostas. The neems that go for hostas show up later and kill that area between veins and make it brown. Nothing like the little dots you posted. The way to find nematodes is to put a portion of affected leaf in some water and look thru a jeweler's loop. You will be able to actually see them IF they are there. Do a search to find out exactly how to do that, if you like.

-Babka

Protecting Ken's butt here, after his bedtime...but I think he can do that for himself very effectively. Nematodes don't look like that on hostas. The neems that go for hostas show up later and kill that area between veins and make it brown. Nothing like the little dots you posted. The way to find nematodes is to put a portion of affected leaf in some water and look thru a jeweler's loop. You will be able to actually see them IF they are there. Do a search to find out exactly how to do that, if you like.

-Babka

Protecting Ken's butt here, after his bedtime...but I think he can do that for himself very effectively. Nematodes don't look like that on hostas. The neems that go for hostas show up later and kill that area between veins and make it brown. Nothing like the little dots you posted. The way to find nematodes is to put a portion of affected leaf in some water and look thru a jeweler's loop. You will be able to actually see them IF they are there. Do a search to find out exactly how to do that, if you like.

-Babka

Protecting Ken's butt here, after his bedtime...but I think he can do that for himself very effectively. Nematodes don't look like that on hostas. The neems that go for hostas show up later and kill that area between veins and make it brown. Nothing like the little dots you posted. The way to find nematodes is to put a portion of affected leaf in some water and look thru a jeweler's loop. You will be able to actually see them IF they are there. Do a search to find out exactly how to do that, if you like.
-Babka

Sorry about that...I kept trying to send this and kept getting a message rejected, and then internal server error, so I just kept trying. Guess this gets my point across. Duh. So sorry.

-Babka

I mentioned nematodes in my posting above, but not to say that the holes came from it. I meant that the stated insecticide is multi-purpose and systemic, killing insects feeding and causing damage now. In respect to nematodes, Merit in that insecticide is also killing nematodes which are still in the roots and crown now getting ready to make their way up into the plant with damage to leaves the beginning of August in my area.
Bernd

Yes but with the very warm temperatures we've had plus being in the deep south in zone 9 nematodes will be active much sooner than north of zone 9. In that zone they can be active all year. It my not be but to be sure I would take a leaf to the local extension office to be sure if no microscope is available. Leaf nematodes would look like tiny worms. Nematodes are typically active when temperatures are above 60 degrees. In the north you generally don't see the damage until summer because temperatures generally don't remain at or above 60 degrees until June.

Scott

Okay, second possibile problem of nematodes, adding it to the sawfly larva issue.

The new plants which arrived bare root I examined for signs of root "knots" or other irregularities on the roots, and all LOOKED normal to me. I have noticed quite a few of the pesky sawflies buzzing around many pots, but the damage to this plant is particularly disturbing, as you can see in the sample leaf above. I really think the first point of attack will be on the sawfly larva.

Now. It has rained the last two days. It is overcast and cool today. If this needs to dry and not be in the sun when applied, then will it be okay to apply it to everything today? Subsequent rain AFTER IT DRIES won't reduce or negate its effectiveness?

I'll also upload a picture of the bottle label here because a picture is worth more to me when shopping than a long brand name. I look for the image match on the shelf.

Scott, thanks for the warning about nems being active earlier. My DH is a veteran of nem wars over his tomatoes, so I'll enlist his aid in my skirmish. He has more technical knowledge (and experience) than I.

Please search this forum for threads about foliar nematodes. Nematodes will hollow a hosta leaf between veins, but never create holes as shown in the first posting of this thread. See the link.

Here is a link that might be useful: foliar nematode damage

Moccasin,

There is an easy test to see if it's nems or not. Take off a damaged leaf. Put it into a shallow bowl of tap water cutting the leaf in half and put both pieces in the bowl. Let it sit for an hour or so. Get a 10x magnifying glass and see if you see any little worm like creatures swimming.

You can do this if you want, but I'm sure it's not nems. Firstly, despite the differences in temps and humidity, it's still way to early to see nem damage. Here in MA we don't see it until August. You aren't that far in front of us. Secondly, that's not what nem damage typically looks like. Typically nem damage follows the veins of a Hosta, leaving a brown section of the vein where they have fed on the foliage. Just deal with the sawflies. I'm convinced that is the problem.

Steve

Moccasin, root knot nematodes (common in the south) are not the same as foliar nematodes that they're talking about.

bkay

Ohh, my head is spinning around, I hope I can remember where all this information is as I go step by step with this problem.

Thanks guys, it sounds like I can deal with the sawfly issue first and then smart myself up a bit about both foliar and root knot nematodes. I appreciate the help.

No, hosta don't get root knot nematodes, that I know of, Tomatoes do (I think it's tomatoes). You mentioned looking at the roots, and they looked normal. You can't see foliar nematodes on the roots, it two different things.

However, once you get either of them in your soil, they're difficult to get rid of.

Do a search on here. There were some great photos either last summer or the one before. There were photos of what they looked like in the leaves. There were also photos of doing the test they're talking about.

But, like babka said, they didn't look like your problem.

bkay

I've never had a problem with nems on my hostas but if you look at UNM's plant pathology website they do show a hosta leaf with identical leaf markings; however, I myself would consider the Sawfly first since you have seen them flying around in the same area. Again not a pest I have ever had to deal with so I will bow to those with more knowledge and experience than I have.

Scott
Sc

Never knew those small stripe-winged thingies were sawflies.
It seems the pots sitting more in the shade were attacked first, and of course, the ones which created a hidden spot beneath their fully spreading canopy. The sawfly behaves just like the fruit fly.

However, it took me about two hours late this evening to carefully spray each and every plant, top/bottom/soil. Please note I stayed around to make sure no creature which could be harmed by this chemical before it dried stayed away.

A side effect of the application is a "Pledge" furniture polish-like sheen even on the duller leafed hosta. Perhaps by morning it will have disappeared somewhat. It is "rainproof" after ONE HOUR. Application should not be done in sunshine. Probably will burn the leaf, and/or change the color. Naturally the sun came from behind a cloud while I was spraying The Shining, so I put an umbrella over it until the sun disappeared.

I took another spate of pictures just before dark, some remarkable growth with the rain we've had this week. Will post in a separate thread with those images.

Appreciate the help. And, my bark and potting soil loads are coming next Wednesday if it doesn't stay too wet to load.