Onion rot- how to respond?

I have discovered onion rot in some of my shallots ( so I removed and dumped them). It appears my garlic and onions are ok. Some of the shallots are apparently healthy and I’m taking a watch and wait approach. When I have lifted the last of them, I am planning on making a garlic “ tea” by crushing garlic into a bucket of water and pouring that onto the shallot patch. Then I won’t grow shallots ever again on the plot. I will probably do garlic next year,  but right at the other end of the plot. I’m also going to disinfect my wellies with Jeyes fluid.
Any other advice? Many thanks.