Botrytis? How bad is it and what do I do?
 

Hello all,

I have been having some orchids bloom for me in the greenhouse this winter and some of them have small brown dots on the flowers. I believe this is Botrytis. How bad is this? Does it permanently impact the plant?

So I hear, it happens in colder conditions with mediocre air circulation. This would make sense for my issue as I have had cold temperatures and not amazing circulation as my heater-fan duo was out of order from June until just a few days ago.

What do I do? I read daconil was good to get rid of it somewhere. When do I spray? ASAP? Wait for flowering to be done?

Also, does that get rid of it for next season? I’m fine if I don’t get the best flowering one season but something permanent would upset me.

It's present worldwide. The only way to prevent problems is to prevent cool, humid conditions.

And maintain good air circulation.

Do I have to do anything to the plants though to stop it from overwintering or something though?

There is nothing you can do. There are botrytis spores almost everywhere on Earth. You can't get rid of them any more than you can get rid of the billions of bacteria on your skin.

Thank you for your reply.

I guess my question is if it has been infected, does that mean all future flowers are permanently infected like a virus? I really just don’t know that much about this condition.

It's a fungus with spores everywhere. Under conditions of cool humid still air they can sprout and cause mild damage. Prevention is the only thing that works - trying to keep the area warmer, not so humid when cool and with good air circulation. It's very hard in a temperate greenhouse in winter during a series of cloudy days (or months.)

In a commercial size greenhouse (26'x96'), we have 4 fans running 24/7. Fans are located as shown in the top diagram.
In a hobby size greenhouse, I would recommend two smaller fans, in diagonally opposite corners as shown in the lower diagram.