Mold on my poles?

[gimmieToms]

I bought brand new bamboo poles this year for my tomato plants, and noticed today that a couple have dots of mold on them, one pole in particular had a fair bit. It’s been a very hot season so far, some humidity but not a lot of rain. My plants are huge but I’ve been making sure there is plenty air movement around the plants, there isn’t too much foliage and I never wet my plants when I water them.
I cleaned the affected poles with diluted bleach and a toothbrush being careful not to get any of it in the soil, but what could be causing this? Could this potentially spread to the plant itself?
I lost all my tomatoes to mold last year. It was a super wet and mild season, I’d just had a baby so wasn’t pruning like I normally do and they were a jungle, so it was kind of understandable. It was a horrible growing year. But I disposed of that soil, bleached out my pots, put fresh soil, brand new bamboo poles and the plants are great. I don’t get why it would get mold on it.