My first thought is that your "plant friendly venom" might not have been.......

As an oh, by the way......If you are growing the plant where the photo shows it, it is obviously is not getting enough light.....Give it some more light and see if it does not really impress you with how it will bloom. The lack of light may also be contributing to the yellow leaf problem.

Bill

It gets a lot of morning sun and blooms all year

What venom are you using?

Typical venom for aphids

There are still 2 new stems comming out that weren't touched by the poison

They're are green

Be more specific on the venom

Just the regular mix with water for garden plants venom

What pesticide is in the 'venom?' Print the name that's on the label. The plant could be shedding some older leaves but it is odd that it is so uniform and on the newer canes. Probably whatever chemical you used but without a name, we are only guessing.

Jane

I'm sorry I threw away the venom because it was already used up completely it had little left when I used it

Will it survive is what I'm worried about

Where are you in the USA?

Will it survive? Probably, but you need to tell the helpers here where you are and perhaps you used the "Venom" at the wrong strength.

Where did you buy the venom?

Could it have been a insecticide / fungicide combo? I ask because fungicides sometimes contain copper which will damage a dendrobium. It also looks like the leaves that are yellow are more at the center of the plant and the leaves to the outside look green? You might have water sitting in the leaves towards the center causing issues. I also agree that the light in that spot looks low.

I tried my gypsy mind reader and even she was stumped. Does houzz offer any info on mind reading?

I live in Puerto Rico and the sun gets to crazy so I put it in the shade at times