Some good news!
My cabbage is doing surprisingly well. It seemed every possible pest attacked it relentlessly early in the season, especially the cabbage whites and the striped flea beetles. But they all left, and for weeks now, not a single pest has bothered the cabbage. Which, by the way, has formed beautiful, tightly-packed heads. One day there were only some sad-looking loose leaves, and then magically it looked like actual cabbage. I have not grown cabbage before, and am excited that it seems to have worked. Hooray for small successes!