I would frame it as a discussion about team goals - and what she thinks is a reasonable goal for each person to review per day. Then if she doesn’t do that, I’d ask whether there are barriers to meeting the goal that you mutually set.
I would maybe go with “Josephine, I was reviewing our team numbers to share with Leadership, and I noticed you have 75 unreviewed resumes in your inbox. This seems like a lot. Is there a reason so many have stacked up? Let’s talk.”
Yours isn’t snarky, but I think sharing that 1) you are reviewing her work, and 2) sharing with leadership, and 3) her numbers are not in line with the rest of the team’s, is important. Plus I always want to talk to my folks to nip problems in the bud. The answer, though, may be Thanksgiving. So this may not be a big problem. It may be a holiday-week-trying-to-catch-up thing.
I would not email this - I would have a convo. And it would go like this - how’s it going, give me a status on all your stuff (I include a list of all stuff in the meeting invite), then based on what she says, either I would prefer that applications are reviewed daily OR let’s talk about priorities and rank your assignments on a strategic and daily basis.