Hello Everyone!
This is a great board and I'm so happy to have a place to share tips and care for orchids. I'm hoping you can help me. I was given two mini phals last April 2015. Both lost their blooms and I have been meaning to repot them. Over the time I've had them I see some white webs (spider mites?) at the base of the plants and I have been rinsing them off immediately. I haven't seen any webs develop in a long time. Then, I saw one dot one a new leaf and it didn't change for months. All of a sudden I saw all these spots one the underside of one leaf! Maybe my eyesight isn't great but I have never noticed scale or mites themselves. Can someone look at my pictures and confirm if it is mites or scale? I would also love a non toxic way to treat it. Since I'm about to repot them I've heard it is a good idea to treat the roots at that time but no website says what is the best method to do so. Do I spray the roots with diluted alcohol, or castile soap or neem oil??? Please advise, thank you.
I had this happen with one of my Phals. I do not really know what it is or what to do to stop the progress. I hope someone will have an answer for you. Good luck!
The tissue in the middle part of the leaf (between the upper and lower surface cell layers) can collapse if the temperature is too high or too low. When that happens it looks like this. The parts affected don't get better; those cells are dead. They turn light brown and dry.
__________________ May the bridges I've burned light my way.
It's not scale, and I don't think spider mites damage would look like this. Wipe the underside of the leaves with a white paper towel moistened with rubbing alcohol (70%) - if you see reddish coloring on the paper towel after, there are likely spider mites. I'd avoid rinsing webbing off the plants - too easy to get water in the crown and possibly cause crown rot.
estación seca's suggestion (above) might be it.
What temperatures do the plants get?
I forgot to add: This can also happen when the water you get on the leaves is much colder or warmer than the leaf. I seem to recall from living in the Midwest that water can come out of the tap pretty cold in the fall and winter. Try letting your water warm up to room temperature before watering your plants or rinsing off their leaves.
__________________ May the bridges I've burned light my way.
Thank You Everyone! I have wiped the leaves with a wet paper towel and see either nothing or a tiny amount of dirt or dust, it is not red. I have seen spider mites on other plants and it doesn't seem like it but there are probably different mite species out there.
I'm still kind of confused as several experienced people have voted it is scale and other experienced people mites. Also the idea that water on the leaves is too hot or cold could be a possibility. When I water them I have always used luke warm water. Perhaps it is too hot or cold by the north facing window sill. They have seemed so happy there since I was given them as gifts about 5 months ago, until last week. The first spot though appeared months ago and only recently multiplied. They have grown new roots, leaves and one has a spike beginning.
I emailed some orchid places directly and was recommended to spray it with a cinnamon infused water solution with a dash of castille soap to kill what they think is scale. I have been trying that.
It's not scale, and I don't think spider mites damage would look like this. Wipe the underside of the leaves with a white paper towel moistened with rubbing alcohol (70%) - if you see reddish coloring on the paper towel after, there are likely spider mites. I'd avoid rinsing webbing off the plants - too easy to get water in the crown and possibly cause crown rot.
estación seca's suggestion (above) might be it.
What temperatures do the plants get?
Sonya, thank you for your reply and welcome. The plant sits on a north facing window. I'm in eastern Pennsylvania. The temps in the house are around 75 degrees to 68 degrees. The window may be too hot for it but it seemed like the safest place from the family knocking it over on the kitchen counter. In the 5 months it has grown well, new leaves, roots. It has oozed some sap and I read it was a sign of a happy orchid when there are no other signs of pests, but now it is showing those spots. When it oozes sap does it create tissue damage?