Critter damage

I had a really poor carrot crop this year. I seeded twice, because my first try yielded about three carrots. And the second got me about four. Now that it's time to harvest, to add insult to injury, I'm finding a black hole in this carrot. The culprit is the carrot rust fly, a tiny insect that can smell carrots far away. The fly lays its eggs close to the carrot, and when they hatch, the larvae take up residence inside by chewing their way in. For years, I've been following the rules: plant the crop in a new location each year, and harvest the carrots before the second week in September, when a new generation of carrot rust flies is ready to move to a carrot near you. I pulled this one September 1, and it was already too late. I'm thinking that because everything seemed to mature early this year, so did the fly.