Gray stuff on newly bought marigold petals. Immedietly cut flower off. Thoughts?

Question

I bought a bunch of marigolds from a nursery today and noticed one of them had grayish petals. I cut it off and threw it away immediately. Could this be a sign of a fungus or disease in my other marigolds. I haven’t noticed any other gray spots on flowers yet.
What could it be?
Could this be harmful?
What should I look out for?

Answer 1

It sounds like is could be Powdery Mildew.

This article will help you.

https://www.gardeningknowhow.com/plant-problems/disease/get-the-cure-for-powdery-mildew.htm