Hello!
Can anyone identify these yellow spots? I have them on 2 phalaenopsis orchid leaves. I got both together a few weeks ago, when they arrived there were some cobwebs on them. They were shipped in. I thought had spidermites, so I sprayed them both with a mixture of neem oil, water and handsoap. Although the webs don't looks like the spidermite webs, but I sprayed just in case. I THINK I have not see any signs of mites. They did not have yellow spots until a couple of weeks ago. They were in quarantine under a red/blue grow light. I thought they were doing ok, so after they've been in quarantine for at least 2 weeks, I moved them into my regular grow are with a stronger grow light. Then I noticed they developed yellow spots. They seem to have different causes and I listed them below:
1. Here is the first plant. It has these marks underneath the yellow spots. The marks look like they were maybe punctured accidentally, they don't look like insect bite marks. The yellow spots are on the same spot on the other side of the leaf. Here are the pictures of the yellow spots on the top side of the leaf and the puncture marks on the underside of the leaf.
2. This plant also has another yellowing spot. I feel like this one maybe an infection? Here is a photo of the spot from the top and the underside, which doesn't show any anomalies (I think).
3. This is the 2nd plant. I feel like it developed the yellow spot after I put it into a stronger light. I've attached photos of the yellow spot and the backside of the leaf. Does this look like sunburn?
Both plants seem to be doing fairly well. The 2nd has a spike and it has grown several inches since being with me.
Please give me your opinion of what these yellow spots mean? Thank you very much!