No carrot varieties are specifically resistant to insects. Soil insects are major problems. White grubs and wireworms cause root damage and quality loss.
Nematodes are more troublesome in carrots than most other vegetables.
Biological controls are seldom used since quality is essential. Currently there are no commercial replacements for diazinon for soil insects or alternatives for dichloropropene and oxamyl for nematode control. Diseases Major leaf spot diseases include Alternaria and powdery mildew. Some carrot varieties are more tolerant to Alternaria than others. Growers may use gibberellin to regrow new tops if Alternaria or weather severely damages foliage.