Major Carrot diseases are:-
- 1.Carrot Bacterial blight: Xanthomonas campestris pv.carotae
Symptom:
- The bacterium causes an irregular brown spot on leaves, dark brown streaks on petioles and a blighting of floral parts.
- Lesions on foliage begin as small yellow spots.
- Soon the centre of the spots they become dry and brittle with an irregular halo.
Management:
- Spraying early with Copper oxychloride 0.25 %.
2.Carrot Bacterial soft rot: Erwinia carotovora sp. Carotovora
Symptom:
- Cells become water soaked, the middle lamella is destroyed and the cells collapse into a soft, watery slimy mass.
- The rotted tissues are grey to brown. they may be accomplished by a foul odour.
- The decay develops most rapidly along the core of the root.
Management:
- Dipping in a solution of 1:500 of sodium hypochlorite before storage or transits reduce the disease.
3.Carrot Cercospora leaf spot: Cercospora carotae
Symptom:
- The first symptom usually appears as elongated lesions along the edge of the leaf segment.
- Non-marginal lesions appear as small, pinpoint chlorotic spots which show develop into a necrotic center surrounded by a diffuse chlorotic border.
- Coalescence of spots is common. linear dark lesions develop on the petiole, sometimes girdling the latter and killing the leaf.
Management:
- Spraying at 10 days interval with Copper oxychloride or Mancozeb.
- Seed treatment with Captan 4g/kg
4.Carrot Sclerotinia Rot or White mold: Sclerotinia sclerotiorum
Symptom:
- Carrots may show little or no damage incidence in the field but following washing and storage white mold outbreaks often occur on the stored roots.
- Only a small percentage of the roots may be initially infected but the fungus mycelium can move very rapidly from carrot to carrot.
- In a matter of weeks, the whole storage container may become a mass of white mold and black sclerotia surrounding each and every carrot.
Management:
- Frequent inspection in storage, low temperatures, aeration and washing in a final water of 2-5 % diluted bleach solution may give adequate control (1 part bleach, (sodium hypochlorite) to 20 parts water.
Source-
- TamilNadu Agritech Portal
