How serious is Botrytis on roses?

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julie777
Posts: 46
Joined: Wed Jan 15, 2020 4:04 pm

How serious is Botrytis on roses?

Post: # 71974Post julie777
Wed Jul 29, 2020 5:32 am

One miniature rose wasn't thriving as well as the others, very slow to flower and then produced a lot of otherwise very beautiful flowers that were brown and rotting from before the buds opened. It took me a while to guess what it was, and now I cut off all the flowers and gave a good spray with triticonazole.

I am wondering if sulphur would do the job better?

I have already been composting its dead heads for a while, though now have thrown all the dead heads out and what I could easily retrieve from the compost pile.

This rose has been affected for at least this whole season if not before, and my other roses don't seem to be affected, though one or two have crinkly curled and dried up leaves, and don't thrive so well, but most are perfectly ok.

Is sulphur a good panacea for unknown rose fungal diseases, and botrytis specifically?
Zone 9.

pacificjade
Posts: 730
Joined: Sat Dec 17, 2011 12:15 am

Re: How serious is Botrytis on roses?

Post: # 71979Post pacificjade
Wed Jul 29, 2020 7:17 pm

We get it every Fall like clockwork here. They rot, have some poofy spores fly around, winter comes, and I don't see it again til November. I don't think its the big of a deal. It could become a big deal if one only does overhead watering, or if spores get on developing hips and inside the peduncles. Neptune seems prone to this for some odd reason, despite the blooms being fine.

In raspberry breeding, botrytis is something they actively breed against, but I never see it discussing in rose breeding studies. I am guessing that with roses, traits we already breed for in modern roses tend to ward off botrytis during the growing season in general. It could be possibly a problem in some indica and OGR lines where such traits like petal substance or petal drop are selected for.

julie777
Posts: 46
Joined: Wed Jan 15, 2020 4:04 pm

Re: How serious is Botrytis on roses?

Post: # 71986Post julie777
Fri Jul 31, 2020 11:03 am

Thanks Pacificjade. Yes I think these spores are everywhere and it is probably down to susceptibility and the breed of the rose and how healthy it is. I will in future take precautions to dispose of dead heads not in the compost, but accept that I can't get rid of all spores, and they blow in the wind anyway.
Zone 9.

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