Bad result of test-digging a carrot

 I've realized through growing vegetables that my efforts and labors in my gardening activities don't always deserve a great harvest.

 A carrot, which I failed to grow in the past three years, seems to be still one of my most difficult vegetables for me.

 Today I pulled out one of my carrots for a test and I saw it unusual at a glance.

 Some root-knots are seen on the carrot and it shows it seems to have a root-knot disease, of which I'm afraid most. The disease makes a look and taste of the infected vegetables bad.
 I carried out some prevention measures like planting marigolds which are effective to ward off
Root-knot nematodes.
 I still have about 15 carrots in my garden but some of them could be infected with the disease. I just hope the damage would be minimized. :(