white spots on mint?

[embean]

I noticed these white spots on my mint.

Link to bigger pic:

http://www.flickr.com/photos/emilybean/3634277962/

Any ideas?

[Kisal]

It looks like it might be spider mites. When you examine the plants closely, do you see little strands of web? The presence of the strands of web would confirm that it's spider mites.

You can control them by spraying with a pure soap mixed with water. Be careful to read the label to be sure you have soap and not detergent. Cynthia suggested a mixture of 1 tsp of soap per quart of water.

Be careful to spray the undersides of the leaves, the stems, and the tops of the leaves. Repeat the application about every 7 to 10 days, to kill any new mites that hatch. Three to 4 treatments should have your plant clear of mites.

[embean]

I looked closely but don't see any strands. The white spots seem worst on the leaves closest to the soil, where the higher up ones are unaffected.

[Kisal]

I can't ID it. There are images of some mint diseases at this link, but nothing jumps out at me as an "Aha!"

http://classes.plantpath.wsu.edu/dajohn/Mint/photos.htm

The fact that it's on the lower leaves is indicative ... to me, anyway ... of it perhaps being some soil bourn pathogen. I suggest you take one or two of the infected leaves or branches to your nearest Extension Service office, and see if they can identify the problem for you.

I suppose it might be something totally innocuous, like sun-scald from water that splashed up on the lower leaves.

I'm at a loss. Sorry!

[embean]

I thought too that it might have been water marks. anyway, I also suspected the soil thing so today I replaced the soil, washed out the pot, removed all affected leaves and rinsed out roots, then sprayed remaining plant with soapy water solution. hopefully that fixes the problem.

[mgiang87]

I believe that I had the same problem as you and was able to solve it. I was able to find a few suggestions on what to do, but nothing definitive. I have three mint plants planted in a row container that were showing similar white spots. I cut the affected shoots down to their final node. Then, I filled a spray bottle with antibiotic hand soap and water and sprayed the top and bottoms of all the remaining leaves as well as light spraying of the soil beneath them. I then moved the container out of direct sunlight and ever since my mint plants have exploded back healthily. Unfortunately, I cannot ID the problem, nor can I really say what solved it since I tried two solutions at once. There were a good amount of small insects on the plants as well as something that could have been the web of a "spider mite," but I am not experienced enough to say for sure. Seeing how well the mint plants grow out of direct sunlight, I would start by keeping them out of the sun and cutting away and suspicious spots.