Hello Satya,
I’m sure I posted a thread somewhere but can’t recall the thread title. From my memory Castori/Kastori may impart some disease resistance but I can’t recall exactly. I believe Dr. Ledesma and Dr. Campbell May have been working on a breeding program to come up with a rootstock that may be more disease resistant.
I am currently testing out Castori/Kastori as an interstock to see if it can impart any measure of disease resistance but I am in the very early stages and this is on a small backyard scale.
I’m not going to go with the nuclear option of fungicides unless the more benign options don’t pan out. I tried to let Mother Nature take its course but after about 5-6 years with multiple LZ trees hardly producing, I’m about to throw in the towel. I don’t blame it on the Lemon Zest, it’s just so dang good tasting. If I didn’t love the flavor so much, I would do the more sensible thing and plant a different variety that produces well without spraying but I am too determined.
I’m hoping that the newer generation of spreader/stickers such as Nufilm 17 can hold the more natural fungal deterrents such as Potassium phosphate on the leaf surface for a long enough period of time that it will be effective in decreasing the overall bioburden.
Simon