Hello, I am new to the forum and to gardening, but am appreciating the advice given here. My family recently moved into a new home with a magnolia tree in the front lawn, but I don't know the tree's history. 2 months ago a few leaves got brown spots, but in the last month they have rapidly advanced and most leaves are covered (and many are rapidly dropping). It looks to be getting ready to bloom (tan colored fuzzy flower... pods(?) are forming all over the tree). Neighbors say it has the large white flowers, but I don't know the species. I live in Palo Alto, CA, and we had rainy season (rain most days) until a few months ago. Shortly thereafter is when the spots started. Now that we are in dry season I water with a soaker hose 5-8 hours every 3 weeks. There was some chlorosis about end of rainy season, and I used iron fertilizer and that worked well. Enclosed photos show the leaves. This tree used to be in the shade of a 40 yr old oak that succumbed to oak root fungus this winter and was removed. I've read this can affect some magnolias, but can't find other information.
Any help you can provide on what disease this is, and how to address it, would be much appreciated!