Or rising in an elevator-cage Toward Ladies' Apparel. (3-4)
These lines make it seem like shopping is a woman-specific activity. This is one of the instances where maybe Wilbur, intentionally or unintentionally, paints a slightly negative stereotypical picture of women.
You could be planting a raucous bed Of salvia, in rubber gloves, (5-6)
Gardening? Is this a strictly female activity? Or did Wilbur simply list this as an activity anyone could be doing, man or woman? It's up to you to decide.
Or lunching through a screed of someone's loves With pitying head. (7-8)
Hmm, having lunch while gossiping with a lovelorn friend, eh? It's hard to imagine this as something other than stereotypical, but maybe it's not all negative. Maybe Wilbur thinks that it's good to show that kind of support to a friend. It's hard to say with just this line since he doesn't seem to offer judgment one way or the other.
Think what a lot // Of time, by woman's reckoning, You've saved, and so may spend on this, (16-18)
"By woman's reckoning" is the hot-button phrase here. Why on earth would a woman's time be any different from a man's? This is the place where Wilbur makes the clearest distinction between men and women, and it seems a little outdated. We don't think Wilbur was hating on women in any way in this poem, but in instances like these he makes categorical distinctions between men and women that we might not be comfortable making today.
Wait for a while, then slip downstairs And bring us up some chilled white wine, (25-26)
This kind of seems like the woman is supposed to wait on the man. Why can't he go downstairs and get the wine and food himself? This line could be considered sexist, or completely benign. If you think Wilbur would just have easily reversed the roles, then it's no big deal. But if not, it seems like sexism.
Ruddy-skinned pears. (28)
This image doesn't necessarily negatively portray women, but conjures up a likeness to the female body: that (some) women have curvy hips like a pear's curves, and the curves are considered beautiful. Again, this isn't necessarily a bad thing, but it's important to see that we're viewing this woman through the eyes of a man and that it's a distinctly male perspective.