Should I keep tuberous begonias badly affected by powdery mildew for next year?
Hi, my tuberous begonias have all been destroyed by powdery mildew this summer, despite spraying with insecticide. I have a number of varieties in both baskets and planters, but none in the garden beds. The tuberous begonias are all completely covered in mildew, both tubers from previous years, and begonia plugs bought this spring. Could you let me know if it's best to destroy the tubers, or, can they be started off as normal next spring? I live near Lanark, Scotland thank you. Douglas Fairbairn
Certified GKH Gardening Expert
Powdery mildew is very easily cured. This is mold, so an insecticide will not help at all. You will have to use fungicides. There are many of which you probably already have in your kitchen. I would toss the plants at the end of the year. No need to overwinter any spores.
These articles will help: https://www.gardeningknowhow.com/plant-problems/disease/get-the-cure-for-powdery-mildew.htm