Leaf pathology

Here are some pictures from the leaves of two of my multiflora seedlings. The seedlings are in their first 4-6 weeks or so of life, and are otherwise quite vigorous, and only have a few unaffected leaves, here and there.

The backs of the leaves seem ok, but they are pretty tiny leaves to be absolutely sure about this. The leaf seems slightly transparent to light in the affected areas when I look from the unaffected side against the light.

Can anyone help identify this trouble?

another leaf

and yet another

Seems that something was hungry.

Hi George,

Do you get white flies? They will nibble new seedlings with damage something like that.

Jim Sproul

Hi Peter…hungry to be sure!!

Hi Jim. Yes we certainly do have white flies at the moment. They are in great numbers feasting on my chilli plants at the back of the house (these rose seedlings are located at the front of the house, where there is less obvious white fly). What you say makes lots of sense…I was thinking of some microscopic mite of some sort…lol.

I never would have thought of the white fly…they certainly are a menace!

Might not be the same, but it looks a lot like what I’ve been seeing on the leaves of some plants under lights in my basement (peppers, iris, etc.) I wasn’t sure what was causing it, but I’m starting to think it’s thrips. They’re the only critters (aside from fungus gnats) that I’ve been seeing.

It reminds me of Mite damage, but they should be fairly easy to detect on the underside of the leaf.

Could it be an instar of a leaf miner sort of insect?

To me it loos as if it’s eating the cells under the surface maybe with an entry through stomata on the underside?

How about a macro shot of the reverse of a leaflet?

I had a look with my 30x illuminated pocket micropscope and could not see anything going on on the reverse side of the leaf

reverse of leaf…not all the dots are dirt and stuff, not bugs.

Front of above leaf

CORRECTION…Two entries above should read… “note, all the dots are dirt and stuff, not bugs”…

Looks like Mites to me. Mites love to collect dirt and debris on the underside of the leaf surface.

Tom may be right. I have seen the same kind of damage from thrips.

Although, I have also seen a fungus like problem on early seedlings that looks something like that too.

Jim Sproul

Could be grasshopper damage, but the local species take chunks out of leaves. I don’t know if you have these demons in Oz, but we have an insect called a leafhopper that does something similar, only more so. I looked at the back of those leaves many times without spotting the culprit. Then the following year I looked again at the right time and finally spotted them on the back. Before I found the bugs, I was absolutely convinced that the plants has rose mosaic virus.

You can see what looks like somewhat regular damage along the margins, but they feed all over the back of the leaf. They are small, but visible with the naked eye.



The foliage of the plant:

http://rosefog.us/TemporaryImages/LeafhopperSharonsDelight.jpg

An actual leafhopper:

http://rosefog.us/TemporaryImages/LeafhopperScaleWeb.jpg

Cast skins, which were the first thing I saw:

http://rosefog.us/TemporaryImages/LeafhopperCastSkins.jpg

The identity of the insect and the damage was confirmed by a California state entomologist who is also a rosarian. It is a pest of apple trees as well.

http://www.virginiafruit.ento.vt.edu/walh.html

Link: www.sactorose.org/rosebug/irosepests.htm#LEAFHOPPERS

Thanks all for trying to help me.

Now that I am primed for things to look out for, I’ll try and identify the critter. As the seedlings grow it will be easier to collect bigger leaves and have a better look. If I can work it out, I’ll post here, to let you all know.

Cass, that leafhopper affected leaf you have just pictured looks like it has identical damage, I must say!

UPDATE…

Similar leaf damage is now appearing on a few of the “Viru seedlings” and multiflora seedlings. There is absolutely no doubt in my mind that this damage is insect related.

The affected seedlings are vigorous, so I’m not too worried about it. It remains an interesting curiosity, (at least to date).

I dont want to remove any more leaves at this stage to look for bugs, as this will set back the seedlings. However I will try and identify the culprit over time.