Q.What Causes Yellow Leaves And Black Around Holes On Leaves Of Balsam?
I have used garden powder but doesn’t seem to help stop the holes or yellowing.

Certified GKH Gardening Expert
Depending on the powder that you used, it may not have been a fungicide. This is what will be necessary to kill off a bacterial infection, which is what sounds like it happening. I cannot say with certainty, as your photo did not come through.
Here are some articles that will help you to use fungicides correctly, and to care for the tree:
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
https://www.gardeningknowhow.com/special/organic/biofungicide-information.htm
https://www.gardeningknowhow.com/garden-how-to/info/homemade-fungicide.htm
https://www.gardeningknowhow.com/ornamental/flowers/balsam/balsam-plant-information.htm