So, it appears that there’s a fungus among us! After hemming and hawing about what on earth is going on with the garlic (fungus, nematodes, other bugs, rust…), i looked at this website from UC Davis, and that really helped. It’s looks most like white rot, Sclerotium cepivorum, to me, and our of 90 planted cloves, there are only 20 remaining. Those that remain look quite sad indeed!
Where did it come from? That was my fault: i bought garlic form the farmers market and stuck it in the ground without asking them if they’ve ever had fungus issues. Next year, i’ll buy certified garlic seed bulbs, and possible dip them in some warm water as an extra measure before planting in the front yard (the current garlic bed is in the back). I’ll have to be careful to rinse off any tools that touch that fungus soil, and not add anything from that bed to the compost for the next few years. Good luck with that!