My biggest problems with beetroot (other than having to sow in modules because they wont germinate in the ground!) are the sparrows! Our local population have taken a distinct liking to the leaves of my beetroot this year. The leaves on half my plants have been totaly stripped. Definetly the birds not snails because I have caught them in the act several times!
Now the lants are just sitting and sulking, roots not swelling at all (probably need a good drink though).