Scale, Edemia or virus

[SteveM]

Hey all,

I appreciate all the help I received in the past. I am having a problem with all of my Phals about 6 of them. No other genera are having issues. They get these pot hole marks on the underside of the leaves then in a day or 2 develop chlorotic blotches on the top side. When I hold the leaf through the light it is translucent. I am thinking edemia but I want to make sure. I am growing them in a greenhouse in a shady spot which recieves spotting light a few hours a day. I have had to water them about every 3 to 4 days. It has been in the high 90s lately. The plants looked great until I noticed this the past few days. This plant did not show anything this morning when I looked at it and now at 230 well pot holes. I am tossed up between scale, edema or CSV. looking at the pics I think I can see a tiny white dot in the middle so I will check better for scales. but I have wiped down with alcohol I had a mite problem a month ago but that I took care of. I see no more webbing although I know some types don't have webbing, No black or brown or red marks on tissue with alcohol. I appreciate all help.

Thans

[estación seca]

What is the relative humidity? They're susceptible to a number of diseases when it's hot and very humid. I suspect a fungal infection. You could contact a nearby university or agricultural extension to see whether anybody could look at the spots under a microscope.

[SteveM]

relative humidity 40-50 % at night up to 70-80. I've looked at it really close under magnification. I cant see any fruiting bodies, I do not see any pests. I did have a ant infestation in that plant a few days ago, that I sprayed with a pyrethroid. So even thinking phytotoxicity. Looking at First Rays website I have to say it resembles edema from the description. I can see the leaves begining to split, but kind of confused since edema usually happens in cooler weather.

I have looked at the other Phals and only one other I see the same thing, worse chlorotic blotching. For some reason the ones that I saw this morning on some of the other phals have disappeared (LOL)

The other alternative that I can come up with is that condition that just recently came up in the orchid world where they are not sure if it is a fungi, mite, or virus. On a of the leaves with those blisters I did see free water. It didn't smell so I am kind of leaning away from a bacterial although I may get a secondary one.

[Ray]

Edema usually covers an area, rather than a bunch of little spots.

I’m leaning toward a pest.

[Roberta]

Remember, ants "farm" aphids and other sucking pests. So it's possible that you got them with your spraying, but not before they munched.

[Dalachin]

That doesn’t look like any mealies or scale or mite damage that I’ve seen on phals. I have had edema on Phal leaves, posting a pic, wish it was better. Translucent bumps is how I remember it, I had a couple of phals with it when I thought regularly spraying leaves was a good idea.

[Waterdog111]

That last post didn’t seem to be finished?It was a good picture of the problem though.

[SteveM]

Yes looks very similar to your picture. . I did forget that I have been foliar spraying micro nutrients and Mg once a week. Im thinking that may be part of the issue. Plant for the most part looks good except that one leaf and another lowest leaf. the other leaves there has been no progression and only a few marks, but the one that I posted I now have some black raised marks on leaf and a lot of chlorotic blotches. I appreciate everyone's help. Im betting at this point it was something that I did. The micro nutrient are extremely diluted, but the Epsom salt may be too high for repeated use. Although a lot of concoctions state a tbsp. of Epsom salt. I only put in quarter tsp to gal, so I think what I could be seeing is sulfur toxicity. From my calculations that comes to 70ish ppm sulfur. I dont know how people put in 3 tsp for foliar feeding. Anyways I am just keeping an eye on it and not doing anything else for now. All other genera's that I have foliar fed looks great. Have to find a different Mg source.

[Waterdog111]

I am starting to realize why it is mentioned so much to flush out the buildup in the media, as these plants never have anyone in the wild to add all these additives to help them along.

[SteveM]

I flush out every other week. My waste water never is above 125 PPM TDS. My tap water is 60 ppm.