Spots on leaves

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At those temperatures and humidity it is highly unlikely you have a primary fungal problem.

The horizontal pseudobulb got chomped by critter or critters. The first Den leaf is a little out of focus, but it might be spider mite damage. I can't see it well enough to be certain but the Den leaf with lots of black spots looks to be an older leaf probably dying naturally, and fungus is attacking the dying leaf. I bet bugs are biting your orchids.

[Rid]

Originally Posted by DanB

Temperature during the day are between 70 and 80 degrees F night is about 65 - 72. I'll check the humidity but the house is usually between 45 and 65 percent humidity. Watering had been between 1 and two times weekly depending on how fast the media dries and how hot the weather has been. I have 3 other small orchids in the same room and they seem to be flourishing. Although the smaller plants I got as small seedlings so they need a little more attention then mature plants.

My orchid ended up dropping all of its leaves (there were only two or three total). Since then it has sprouted new leaves that I hope will become a new pseudobulb. The other pseudobulbs on this plant were bare when I bought it. I’ve attached a recent picture of the new growth.

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Originally Posted by Rid

My orchid ended up dropping all of its leaves (there were only two or three total). Since then it has sprouted new leaves that I hope will become a new pseudobulb. The other pseudobulbs on this plant were bare when I bought it. I’ve attached a recent picture of the new growth.

That medium is very large. You will probably need to water it every day while it is making the new growth. Dendrobiums shouldn't dry out when growing.