White Spots on all My Herbs! :(

[waheela]

Hey everybody. This has been happening for a while and I'm kind of at my wits end. At first I thought it was Powdery Mildew based on google search results. I'm pretty confident this isn't the case though. Does anyone know what this might be? I love my plants and I'm scared they're on their way out.

Mint



Oregano



Basil



Rosemary

[rainbowgardener]

Your herbs look healthy and not at all on the way out. You are right, not powdery mildew. Have you checked carefully for any little insects. It looks a bit like the damage left behind by leaf sucking insects.

Do you mist them? It might just water spots, minerals left behind by hard water.

Are they growing indoors or out?

Welcome to the forum!

[waheela]

Thank you for the fast response!

The mint is actually in pretty bad shape. The leaves at the bottom have yellowed and fallen off. (I think this is an unrelated problem to the white spots though. It's possible I may have over-watered it.)

I thought the white spots might have been insects too, but I've never seen any on the plants. (Besides aphids, which was months ago.)

They are outside plants, and I do mist them (irregularly).

[Cola82]

I've actually been wondering about this--that photo of your rosemary might as well have been taken on my patio. I have the white stipples on a bunch of stuff that isn't kept close together--mostly the rosemary and a couple different flowers--so I'm guessing whatever it is prefers those plants specifically.

I don't mist mine at all, except for having sprayed them with neem oil or milk spray here and there, but I've only ever done that in the evening.

[evtubbergh]

My rosemary looked just like that. I discovered sucking insects (both aphids and spider mites). Look for very tiny little things on the underside of some of your leaves. The damage can be from a previous infestation even if you got rid of them.

PS mint likes moist, shady conditions but you still need drainage.

[waheela]

Thanks for all the great replies, everyone! I'll check for bugs more closely later today.

Marlingardener, hmmm, I don't have any of the plants in direct sun. Regardless though, wouldn't sun damage create yellow and brown spots? The spots on my plants are distinctly white.

[rainbowgardener]

Ordinary sunburn creates tan areas that are thinned and a bit crispy, usually in bigger areas.

Sun burning through water drops can create spots like yours.

[applestar]

Haha... I've been scrolling down the page waiting for the chance to say rosemary definitely looks like spider mites. ("haha" is because of my own reaction -- oh, somebody said it... And somebody else, too.... Oh well I won't be the first.... )

The spots are close together indicating the infestation is getting pretty serious too. When you mist, look through the foliage and see if you see any webbing. Also, try holding a piece of white paper under the stem while the plant is dry and flicking it to see if any tiny red or black specks fall out. Put the paper on a smooth surface and press/stroke with finger and see if they smear. Mites are nearly microscopic -- I can barely see them without visual aid.

Also, did you say NONE of the plants are in full sun? Even the rosemary?

[waheela]

Thanks again for all the replies, everyone!

applestar, I tried what you said. When I flicked the rosemary above a white sheet of paper, a lot of tiny, tiny flecks landed on the paper, but they didn't move at all. They did leave a brownish smear when rubbed. A couple whitish fly-type bugs (some dead, some alive) also fell after a few vigorous flicks. Lastly, I did see some webbing, but it could've been cat hair. Not sure what to make of all this. Would it hurt to assume spider mites and treat the plants accordingly?

Regarding your question about lighting, the plants are on my apartment balcony, but the balcony gets A LOT of sun, so I've moved all the plants under the balcony railing. The rosemary was yellowing and browning on the other side of the balcony, so I thought that was probably a bad sign. All the plants still get a lot of sun, but they are no longer directly in it for most of the day.

[digitS']

What may appear as "dead" may just be the shed exoskeletons of an insect that has molted.

Rosemary seems to be a favorite for mites. Spider mites are fairly easy for me to kill with insecticidal soap. First tho', it helps to limit the number necessary to kill. Can you take the plants down to your parking lot and spray them with a strong jet of water? You can blast those tiny bugs off on the asphalt and they will never make it to another potted herb to cause mischief.

If you use the soap, it is a good idea to rinse the plants before they go back in direct sunlight. The schedule could be to blast off the mites in the morning, allow the plants to dry thru the day, spray insecticidal soap in the late afternoon, and rinse the plants with water the next morning.

This is usually my schedule for dealing with spider mites.

Steve

[Susan W]

Oh those white spots on the leaves! Aside from rosemary which may have a different issue, they are on anise hyssop, oregano, mint, basil and more. Some on adult plants, and many on starts. I figure it to be something laying eggs, and larva stage busy eating inside leaf, much like leaf miner but not the squiggly lines. And insects don't bother herbs much (according to a master gardener, snark). Without seeing the culprit, hard to figure line of defense or offense! I pick off the worst looking leaves.

[waheela]

Thanks for the replies!

Steve, thanks. I've sprayed the plants down pretty well. I only have neem oil and dish soap though. Would either of these work? If so, do you recommend a water to soap ratio?