Without a picture, it's hard to tell, my guess would be either fungus or mealy bugs.

It isn't mealybugs, I know what those look like.

Probably not fungus, since it seems to be IN the leaves, not ON them. I will post a photo this afternoon.

Here it is... wow, it looks even WORSE in closeup, LOL...

I will also post this in the Garden Pests forum... do we HAVE a Garden Pests forum?

I am not sure where you are, if you are in California, it might be spidermite activity. But those black spots on the parsley, those are probably the bug. Looks almost like some leafmining type bug... not a leaf miner, but some bug that does that sort of thing.

Thanks, heathen. I'm in Pennsylvania. I will check out spidermites...

Spidermites can kill a plant faster than aphids or mealies. I make my own homemade spidermite killer, works great, but you have to repeat for a few days, then wait a couple of days and repeat to get the hatched eggs.
I use .5 gal of water
1TBSP cooking oil
1TBS dishsoap
1TBS alcohol
and maybe 1TBS hydrogen peroxide. try not to get this into the roots.

After having done a little research, I don't think these are spidermites.

I saw the last comment on this was about a year ago but I think I have the same thing. About a year ago our mint started getting these smal well defined clusters of white spots on the leaves that spread quite quickly. Soon all the other herbs in the surrounding area had the same thing with the exception of the chives. The problem has now spread even to my tomato plants.

I've looked at the leaves very carefully, but can't see any obvious insects on either the top or bottom of the leaves. I did see some tiny white dots around the stem of the leaves on the corriander leaves, but don't think these are bugs (too small to tell without a magnifying glass and didn't see these anywhere else).

We've had to throw away half of our herbs to rey to get rid of the problem, and have sprayed a fungicide on the rest for now. Does anyone know what this is and how I can save my herbs!

I have the same exact problem with my herbs. The thyme, marjoram, oregano & tarragon look exactly like the picture above. It doesn't seem to hurt the plants, since they're all flowering and growing vigorously (and huge!) but I don't want to eat them.

I found lots of similar questions on the internet, but no specific answers as to what it is. Does anyone know?

You could try posting in Garden Clinic, which is for both pests & diseases: http://forums.gardenweb.com/forums/pests I tried searching there for the old post but couldn't find it. Please be sure to update us here if you learn anything. You might want to include a link to the thread that we're in, http://forums.gardenweb.com/forums/load/herbs/msg0918454625598.html

Organic Gardening is another one to try. E-mail me if you need any help with the link. Good Luck, River

http://forums.gardenweb.com/forums/load/pests/msg0402552616927.html

this post has the same problem and someone suggested it's leaf hoppers or thirps...

Here is a link that might be useful: oregano spots

Oh darnit. I do have thrip damage to my calendulas, but that looks different (more small long/thin white marks, rather than dots). But I just googled, and it definitely does look like leaf hopper damage. I don't think I've ever seen any, but now I will go look for them.

Anyone know how to control them?

Has anyone found an answer to this problem yet? I have the same problem with my herbs as well as some other flowering plants that are in the vicinity of the herbs.

Watering plants when the sun is really intense can cause little white spots on its leaves. Intense sunlight can pass through the water drop, be focused on the surface of the leaf below, producing sunburns. It's the same principle as using a magnifying glass to start a fire. I did the same thing and wondered why so many of my plants and different types of plants had the identical little white spots. I quit getting water on their leaves when the sun was bright and now, no more little white spots. So maybe you're doing that too.

This post was edited by coderblu on Mon, Aug 26, 13 at 13:21

Strong fertilizer , then comes the sun, water eveporates and the fertilized gets even stronger and CAN burn tender leaves.

The idea that watering in sunshine burns leaves has been debunked.

Here is a link that might be useful: Watering in sunshine