Effect of systemic fungicides on symbiotic fungi
 

Hi guys, just wondering if systemic fungicides can have an effect on the Mycorrhizae fungi living within the orchid, and if it does, will this have a negative effect on a mature plant?

I would think that it would kill off symbiotic fungi. Most orchids today are artificially propagated and do not need the fungus from the wild. It should have no effect on mature plants. The main need that orchids have for symbiotic fungi is for seed germination in the wild.

Realistically, the use of high phosphate fertilisers probably limits the growth of mycorrhizal fungi to begin with so there's probably not a lot of fungi in the roots to kill. Unless you're growing orchids that are more reliant on fungi (eg many terrestrials), I wouldn't worry.

Oh okay, cool. Thanks for your help guys