Carrot diseases A lecture on ToT training of FFS By Mr Allah Dad Khan Provincial Coordinator IPM KPK MINFAL Islamabad

2. Carrot Diseases
A
Lecture To ToT trainees ( FFS)
By
Mr. Allah Dad Khan
Provincial Coordinator IPM KPK
MINFAL Pakistan

4. Damping-off Pythium spp. Rhizoctonia solani
Symptoms
• Soft, rotting seeds which fail
to germinate; rapid death of
seedling prior to emergence
from soil; collpase of
seedlings after they have
emerged from the soil
caused by water-soaked
reddish lesions girdling the
stem at the soil line
• Cause
• Fungi

5. Soft rot rwinia carotovora
Erwinia chrysanthemi Pseudomonas marginalis
Symptoms
• Sunken dull orange lesions
on taproot which causes
tissue to collapse and
become soft
• Cause
• Bacteria

6. Black rot Alternaria radicina
•
• Symptoms
• Damping-off of seedlings; root
and crown necrosis; blighted
foliage; lower portion of
petioles black and necrotic;
black ring around petiole
attachment black, sunken
lesions on taproot
• Cause
• Fungi

7. Bacterial leaf blight Xanthomonas campestris
Symptoms
• Small, angular, yellow spots on
leaves which expand into
irregularly shaped, brown, water-
soaked lesions with a yellow halo;
centers of lesions dry out,
become brittle; leaves may
become curled or distorted;
flower stalks may develop
elongated lesions that exude a
bacterial ooze; infected umbels
may be blighted
• Cause
• Bacterium

8. Alternaria leaf blight Alternaria dauci
Symptoms
• Green-brown water-soaked
lesions on leaves which
enlarge and turn dark
brown or black; lesions may
coalesce causing leaves to
yellow and die; lesions may
be present on petioles
• Cause
• Fungus

9. Cercospora leaf blight Cercospora carotae
Symptoms
• Small, necrotic flecks on
leaves which develop a
chlorotic halo and expand
into tan brown necrotic
spots; lesions coalesce and
cause leaves to wither, curl
and die
• Cause
• Fungus

10. Downy mildew Peronospora umbellifarum
Symptoms
• Yellow spots on upper surface of leaves;
white fluffy growth on underside of
leaves; lesions become darker as the
mature
• Cause
• Fungus
• Comments
• Disease affects young, tender leaves;
disease emergence and spread is
favored by prolonged leaf wetness
• Management
• Plant pathogen-free seed; do not
overcrowd plants; rotate crops with
non-umbelliferous varieties
• Symptoms

11. Powdery mildew Erisyphe heraclei
Symptoms
• Powdery growth on leaves, petioles
flowers stalks and bracts; leaves
becoming chlorotic; severe infections
can cause flowers to become distorted
• Cause
• Fungus
• Comments
• Fungus can spread long distances in air;
disease emergence is favored by high
humidity and moderate temperatures;
infection is most severe in shaded areas
• Management
• Plant tolerant varieties; avoid excess
fertilization; protective fungicide
applications provide adequate
protection; sulfur application can be
used in infection occurs early in season

12. Cavity spot Pythium spp.
• Symptoms
• Sunken, elliptical, gray lesions across the
root; outer layer of root ruptures and
develops dark, elongated lesions; small
vertical cracks may form on the cavities
• Cause
• Fungi
• Comments
• Fungi can persist in soil for several years and
disease outbreaks are associated with wet
soils; flooded soil increases the number of
cavities formed
• Management
• Some cultural practices can control the
disease: avoid planting in fields/areas known
to previously had carrot spot; do not over-
fertilize plants; application(s) of appropriate
fungicide can provide adequate control

13. Root-knot nematodes (Stubby root nematodes, Needle nematodes)
Meloidogyne spp.
Paratrichodorus spp.
Longidorus africanus
Symptoms
• Forked, distorted or stunted
taproots; reduced stand;
reduced yield
• Cause
• Nematodes

14. Sclerotinia Rot - White Mold
Sclerotinia sclerotiorum

15. Common Scab
Streptomyces scabies