I would say spidermite or false spidermites.

I just noticed this is a Philodendron so fortunately you can just wet the problem. Take it to the sink or shower and give it a good rinse with the sprayer all around the leaves, over and under, where the leaves attach to the petiole and a general going over. Repeat this every 3 to 5 days for 3 weeks and this should rid the plant of any of those nasties.

Try to avoid wetting the potting media more than you have to and if you get it wet, make sure you flush it thoroughly to remove as much water as possible from the pot (tipping it 45 degrees over a bowl/cup helps remove even more water).

interesting. i have a philo that's been having these spots for a year or two and nothing i can do to get rid of them. i could swear it's not mites...i'd know mites if i saw them by now...or traces of them...tinee tiny white specs. see none on mine and yet i see this weeping tiny dew drops that indicate smth biting them or excess water may be? like exudation of some sort? i tried to water less, but i have large leaves - can't let it dry too much..

i tried to spray, wash and then tent - fewer spots when i tent for sure.

i thought may be it's bacterial? can't rid of that except improve culture and hope for the best! still undecided..i even cut off a few worse leaves together with the cane (and rooted it and isolated it just in case- it's doing fine and growing). the plant itself is not declining in any way - just these little yellow spots are kind of unsightly.. hate them!

Thank you for the replies. Yes petruschka i also cant see any indication of spider mites. exactly the same issue. dew drops and all. I am going to repot the plant and fertilize it a bit. I think the soil is too dense and its somehow messing with the watering. I will keep you posted!

laticauda - what are false spider mites?

They are very similar to spider mites but dont leave any webbing.

Oh I didn't realize which thread this was when I replied.

How is this plant doing? Have you started the treatment yet? You can normally see results pretty quickly with these things.

mine are in rather light soil mix approx 3 parts African violet mix (some perlite,mostly peat) 3parts coco-peat , 4 parts large perlite and 3 parts bark (cut to half with coco-chips). it drains super fast and rewets very easily due to coco-peat and coco-chips. it is called jungle mix. i mix it myself based on recommendations from Aroid society.

but i added coir products to make rewetting easier. i pre-soak coco-chips for use with cal/mag as recommended. and this still happens. oh, and and they get partial sun too nice and dappled, so in good light and with good growth. i can't really improve the culture at this point. and i flush regularly...and oh, i shower them and play music to them :)...you get the drift :))))). and it still happens!

so i am at a loss for what to do.

it also happens with my philo 'xanadu'. i got a new clean one and after a year it started happening with it too...i kept it separately from the other infected one (that one is permanently isolated, as i was paranoid that it will spread it to everything). The 'xanadu' gets it bad - like pox ! very unsightly. i'm ready to chuck it - been fighting it for 3 years, i think.

'scuse the rant! ;(..

but i have other philos that do not have it and the pots stand next to each other and they don't get infected. so i don't think it's mites. i feed them too regularly. and if anything i keep them on the dry side, but not wanting for water, since they are on self-watering water wicks. once they use up the water in the reservoir i allow them to go sev days as is to get the mix just slightly drier. occasionaly if i see them weeping water from the tips (that happens when it's cooler and they suck up too much water) i let them go drier.

In general i find philos especially larger leaved varieties to be thirsty plants.

i remember reading something about it somewhere, but i can't locate where..

lati! stop liking it! give me some ideas!.. sorry, i'm beat(cry, baby, cry..u cry-baby, u..!)! defeated by philo-spots! :)))))

LOL! You're so funny.

I have had plants right up against each other where some plants get affected by mites and others don't (same species, propagated from the same plant). I think it has to do with individuals having different tolerances and repelling qualities. Mites can also carry viruses, so that's something that could be at play. Genetic variation, slight differences in husbandry. Even though the plants are kept in the same place, one may be closer to a window or get more direct sunshine so dry out faster than the one right next to it that's obscured by a pot or another plant's leaves.

Did you say you treat them periodically when you water? I may have it confused with some other post I've read recently so apologies if I'm mistaken!

I'm going to call a professional.

Do you have photos of your plants, Petrushka?

wow! a pro? :O!!!! i've got pics! i've GOT them! lemmi go rummage..

this is my Philo Subincisum - you can see little dew drops on the underside of the leaf (also on the petiole below that u can't see)

i enlarged the section to see dew-drops and the leaf looks clean to me, no mites.

this is backlit underside of another leaf - those yellow spots are almost not visible otherwise, only when you back-light the leaf.

this is the same leaf from the top - spots are to the left of the main vein

this is a much older leaf, when the plant had more spotting in the fall - the spots become more pronounced with time. it's almost like they dry up around the puncture (where the dew drop was) and then turn yellow . they don't enlarge with time.

this leaf is also back-lit to see them better.

Maybe it's the different composition of the cell structures from being different species but these dots appear different in some way to the photos of the OP's plant.

I'll call the two plants OP and PT, respectively.

OP has a more faded look. I'm trying to think of a metaphor. Think of crushed ice. If you use a straw and slurp up the colored flavor syrup, there is a pretty even fade from the center of where the straw is located and the surrounding areas.

On the underside of OP, it appears to me that you can see evidence of physical, mechanical damage, albeit very tiny (from biting sucking pests). It would appear to me anyway.

Q's about PT:

Those white dots in the first photo are droplets of water and not white/fuzzy?

Does it appear also in new growth or is it only older leaves?

i agree, OP's spotting is more diffused. but actually as i said it's hard to see initially on the top of the leaf. they only yellow and become distinct with time.

may be we can get more close-ups from OP?

as far as mine: yes, it's clear water and it is sticky. i think i read that some aroids (don't remember which) exude 'sweet dew' to attract insects. and it's all over the surface, not just the drop at the tip (when they're overwatered).

it's on both new and old growth. it makes me think it could be oedema, but oedema spreads with time, and these spots stay the same size.

on my Philo 'Xanadu' there are even more spots and sometimes it's not spots but kinda streaking inside the leaf tissues (not as much as virus and nor leaf-miners).

this is fairly minor spotting on young leaf

the back of the same leaf - no dew

backlit leaf - you can see spots much better - they are diffused, not clear outline

but on older leaves they become very well defined

Are spots already apparent on newly emerging growth? Could this be thrips damage?

newly just emerging growth is clean actually, it gets dew later once the leaf is unfurled, may be sev weeks later.

yes, thrips damage looks quite similar, but patches are more irregular, not round. the holes are larger (the tissue damage that is).

oh, i know everything about thrips ;)..i've had them a few years back..the greenhouse thrips - the original 'xanadu' brought them in - demolished all kinds of things..amaryllis, African Masks, anthuriums, crotons to name a few...

but i diagnosed them finally when i saw the crawlies on the leaves :)) ..and got rid of them eventually by moth ball fumigation. don't quote me on this, but i learned about it from people fumigating gladiolus bulbs - which are notorius for thrips overwintering in bulbs. it really works like nothing else. 2-3 month tight tenting with moth-balls crushed inside in caps placed on the surface of the medium. so you can easily fill/remove them and don't contaminate the medium.

the thrip damage looks different on xanadu - i actually can throw more pics, if you'd like?

the lesions on the back are much larger and a little brown callus forms from inside chewing. and spots are much larger and just awful!

this is thrips :O

My first thought on the spots is bacterial leaf spot of some kind, there are several different pathogens that can cause it. However, what I see in pics here don't look typical.

Do these spots get larger and eventually turn dark? If they stay yellow, does a "halo" develop around the spot over time?

The sticky water drops are from guttation, a normal process in Philo's.

Russ

>>The sticky water drops are from gutation, a normal process in Philo's.

that's what i thought it might be! but does this gutation then cause little yellow spots to develop?

can you post a pic of how it looks on yours? and how the older leaves look after?

on mine there's no dark or any other halo and the spots don't turn dark.

and i also thought they might be bacterial. i tented the plant to isolate it and applied systemic just in case to kill off anything. but it does not work on fungal or bacterial, of course. so after 3 mo - i still see this tiny spots developed on fresh leaves, but it's not worse (it would be if it were fungal or bacterial in more humid conditions, right?) and in fact is a lot better.

but i just don't want to keep the plant permanently tented. what's the point of keeping it then?

but at least when it's tented all the time i'm not spreading anything to other plants.

i have sev others philos and anthuriums and other aroids. i could not tent the huge Philo subibcisum though over winter and that's the one that has a lot of dew drops now.

Maybe the areas that get the water droplets create an environment for the pathogenic bacteria to attack/consume the cell tissues.

Is it possible these droplets are the plant "bleeding" after being bitten by something?

Do your unaffected plants also behave this way/show these droplets? (You said you have more than one right?)

>> Is it possible these droplets are the plant "bleeding" after being bitten by something?

it's possible but i can't find anything. when i have mites on other aroids (and i have them from time to time) there is no dew accompanying it.

>>Do your unaffected plants also behave this way/show these droplets?

nope, other philos don't have droplets, only 2 'xanadu' and 2 subincisum. i did try to spray to wash off the dew, but it reappears.

correction: i watered my Philo 'Painted Lady' sev days ago and checked it today: and i see a few dew spots on the main stem. otherwise it's clean. Is it possible that they exude this dew once they get even lightly watered? and if they get constant supply of moisture ? i grow all of them on self-watering wicks, but the mix is very airy with coco-chips large perlite and bark - plenty of air, but still, they are climbers (except for 'Xanadu'), so perhaps that's what they do? but that does not explain spotting though.

Copying here too for these people to think on as a possible cause (from my post about the same problem):

@petrushka you actually just said something that kind of put me on to something else which is a way better problem to have than bacteria. Considering your dew drops... I have those too, but I live in super hot, humid, muggy, northeast Florida, so transpiration is pretty common here. That’s what your “dew drops” are- the plant is transpiring extra water through its leaves (kind of like sweat). The fact that you’re getting it in NY with the same spots makes me think it’s Edema (or oedema)- basically the plants roots are taking up more moisture than it needs, faster than it needs, and it’s causing some rupturing in the leaf cells. This prob has to do with finding the right balance between light, air circulation, soil, or proper nutrition (not having certain nutrients in the soil, or the plant not being to absorb them due to soil ph).... for ME. I think yours might be due to temperature. If it’s cool or cold there and you water with warm or tepid water, the difference in temperature can cause the edema too. Also. If you’re misting or using a humidifier, you prob don’t need to since that would just contribute to the transpiration. Let me know what you think!

this is very interesting! i just cut off a large tip cutting 2 weeks back, could've tested it for ooze...but i can take another. however, as far as stunting growth - i don't see any stunting, the plants continue to grow. of course, when i removed close to a half of leaves they did slow down, but still growing overall ok.

but at least it's something new i can look into! thanks for alerting us!

My five year old tree philodendron has yellow spots,however it's growing well has a lot of new shoots.Some bottom leaves have yellow beyond help so I trimmed them off.Anyone have same issues,have checked for infestation and their is none.