This document discusses several diseases that affect papaya: anthracnose, black spot, black rot, Phytophthora fruit rot, bacterial canker and decline, bunchy top, Cercospora black spot, and papaya ringspot virus. It provides details on the symptoms, causal organisms, disease transmission and management strategies for each one. The key diseases include anthracnose caused by the fungus Colletotrichum gleosporoides which causes lesions on fruit; black spot caused by the fungus Asperisporium caricae which causes lesions on leaves and fruit; and papaya ringspot virus which is transmitted by aphids and causes rings and mottling on fruit along with

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

4. Anthracnose Colletotrichum gleosporoides
Symptoms Anthracnose lesions on papaya
fruit
 Small water-soaked lesions of fruit
during ripening; circular sunken
lesions with light brown margins
 Cause
 Fungus
 Comments
 Fungi spread by wind and rain;
disease emergence favored by high
temperature and humidity; disease
can have a serious impact on
refrigerated fruit for export
 Management
 Appropriate protective fungicides
should be applied; dipping fruits in
hot water at 48°C for 20 minutes
reduces the incidence of the
disease

5. Anthracnose
Anthracnose lesions on papaya
fruit
Anthracnose lesions on papaya
fruit

6. Anthracnose
Anthracnose symptoms on papaya
Anthracnose lesions on papaya
fruit

7. Anthracnose
Anthracnose lesions on papaya
fruit
Anthracnose lesions on papaya
fruit

8. Black spot Asperisporium caricae
Symptoms Symptoms of black spot on papaya
fruit
 Circular water-soaked or brown lesions
on older leaves; centers of lesions
become bleached as they mature;
leaves curling and turning brown; raised
lesions on trunks; sunken circular
lesions on fruit
 Cause
 Fungus
 Comments
 Disease spread by wind and rain;
disease emergence favored by cool
weather interspersed with moisture from
dew or rain
 Management
 Disease may require applications of
appropriate fungicides for adequate
control

9. Black Spot
Symptoms of black spot on papaya
leaf
Symptoms of black spot on papaya
leaf

10. Black Rot
Symptoms
Black rot symptoms
 Black sunken rot on young fruits
originating from stem end or contact with
a leaf; young fruit withering and
dropping from plant; small, brown
sunken lesions with light brown margins
on ripening fruit
 Cause
 Fungus
 Comments
 Fungi enters fruit through wounds
 Management
 Appropriate protective fungicides should
be applied; dipping fruits in hot water at
48°C for 20 minutes reduces the
incidence of the disease


11. Phytophthora fruit rot (Stem rot) Phytophthora
palmivora
Symptom
Symptoms of Phytophthora
infection on papaya fruits
 s
 Water-soaked lesions on unripe fruit that
oozes latex; withering fruit; water-soaked
lesions on leaf scars of fruit bearing stem;
mature fruit covered in white mycelium
 Cause
 Oomycete
 Comments
 Fungi survive in soil and enter through wounds
in stem; disease often emerges after hurricane
damage
 Management
 Disease can be controlled through the use of
appropriate protective fungicides such as
mancozeb or copper sulfate; root rot in
seedlings can be prevented by planting in
holes filled with soil in which papaya has never
been grown - by the time the roots extend out
of the added soil the plant is no longer
susceptible to the disease

12. Phytophthora
Symptoms of Phytophthora
infection on papaya fruit
Symptoms of Phytophthora
infection on papaya fruit

13. Phytophthora
Symptoms of Phytophthora
infection on papaya fruit
Phytophthora on papaya fruit (after
experimental inoculation with
pathogen)

14. Bacterial canker and decline Erwinia spp.
Symptom
 s
 Angular water-soaked lesions
on leaves; lesions coalesce and
spread along leaf veins; witling
leaves, particularly at top of
canopy; water-soaked lesion
and cankers on stem; cankers
girdle stem and cause plant to
collapse; small water-soaked
lesions on green fruit
 Cause
 Bacteria
 Comments
 Bacteria survive in lesions and
cankers

15. Bunchy top Likely caused
by Rickettsia bacteria
 Symptoms
 Chlorosis of young leaves; water-soaked spots
on petioles and stems; petioles rigid, horizontal
and shortened; thickened leaf blades that cup
downward; internodes shorten and growth stops
resulting in a bunchy appearance to the plants
 Cause
 Bacteria
 Comments
 Transmitted by leaf hoppers
 Management
 Use of tolerant varieties of papaya is currently
the only method of control

16. Cercospora black spot Cercospora papayae
Symptoms Symptoms of Cercospora black
spot on papaya
 Tiny black dots on fruit which enlarge to
3 mm across; spots are slightly raised
and although indistinct on unripe green
fruit, become visible on ripening to
yellow; lesions on leaves are irregular in
shape and gray-white in color; if
infestation is severe, leaves may turn
yellow and necrotic and drop from plant
 Cause
 Fungus
 Comments
 Disease usually enters orchard from
infected papaya leaves in adjacent
orchards
 Management
 Applications of appropriate protective
fungicides at intervals of 14 to 28 days
provide satisfactory control of the
disease

17. Papaya ringspot Papaya ringspot virus (PRV)
Symptoms Papaya ringspot symptoms on fruit
 Dark green rings on fruit which may be
slightly sunken and become less distinct
as the fruit ripens; fruits may have
uneven bumps; leaves often exhibit a
bright yellow mosaic pattern and new
leaves are small and plant growth is
stunted
 Cause
 Virus
 Comments
 Virus is transmitted by several aphid
species
 Management
 Infected plants should be removed and
destroyed to prevent spread of the virus;
new planting materials should be free of
the virus; intercropping papaya with a
non-host such as corn can help to
reduce the incidence of the disease in
papaya orchards by providing aphid
vectors with an alternative feeding site

18. Papaya ringspot
Papaya ringspot symptoms on unripe
fruit
Papaya ringspot symptoms on unripe
fruit

19. Papaya ringspot
Foliar symptoms of papaya ringspot Papaya ringspot symptoms on fruit

20. Papaya ring spot
Foliar symptoms of papaya ringspot Foliar symptoms of papaya ringspot

21. Papaya ringspot
Papaya ringspot symptoms on fruit Papaya ringspot symptoms on unripe
fruit