The idea is to prevent the spore from developing or even getting into the needle.
This is my preferred method instead of spraying.
Prevention.
But if you already have some needle cast, it’s making new spores, spraying helps to minimize the spread. There will be spores in the air, and again, spraying helps.
Is it overkill? Perhaps. I have lost trees to needlecast. I purchased one tree and it infected several of my other trees! So, I’d rather be safe than sorry!
This is my preferred method instead of spraying.
Prevention.
But if you already have some needle cast, it’s making new spores, spraying helps to minimize the spread. There will be spores in the air, and again, spraying helps.
Is it overkill? Perhaps. I have lost trees to needlecast. I purchased one tree and it infected several of my other trees! So, I’d rather be safe than sorry!