First of all, my condolences. That's rust all right. Once it's in your region, you will probably always have it around. The spores blow for long distances, so even if you cleared your property (and that of all your close neighbours) it would come back. We were in a rust-free area for the first ten years we lived here. Then one spring, after a warm and wet few weeks, all the garlic was infested with it. The bulbs ended being half their normal size and we didn't
sell any at markets after a couple years of some nice sales. I resolved to plant most of the crop in a different part of the property, among some young nut
trees, in a well-ventilated paddock and at the "high point" of what's a pretty flat bit of
land.
The next spring was totally different, starting a bit late and then getting dry during what's normally a reliably wet time of year. I thought that this plus the planting locations would keep us safe from an outbreak. Wrong. The orange spots showed up right at the peak of the freakishly hot and dry period right before summer solstice. The harvest wasn't as badly affected, but still nothing like the pre-rust years.
This season's performance was similar to last year's. I moved the plots again, planting mostly in some new raised beds with fresh soil plus
compost and inoculated
biochar. Spring weather was a bit more "normal" (like there even is such a thing anymore), but the rust showed up on schedule in late November. This time I got a little more aggressive with the countermeasures: mostly spraying the leaves with potassium bicarbonate and manure/compost teas. We got an OK harvest, but still nothing like what we used to take for granted. Elephant garlic, which is really a leek, is unaffected. The stiffneck varieties don't seem to get it as badly on the tops, but the bulbs are still considerably reduced in size. Softneck seems to get it the worst here, but I will select and plant out the largest bulbs in hopes that there is some resistance or tolerance going on in what are effectively clonal varieties.
I learned a lot about the lifecycle of rusts thanks to this
experience and the myrtle rust which began spreading in NZ a few years ago. Long story short: don't expend all sorts of effort on quarantine, because it's airborne. Keep your soil healthy, experiment with earlier or later plantings, and try foliar sprays to knock it back.