1. The document discusses several major diseases that affect clove plants, including sudden death caused by Valsa eugeniae, Sumatra or die back caused by Ralstonia syzygii, and leaf spot, twig blight and flower shedding caused by Colletotrichum gloeosporioides. 2. It provides details on the symptoms, pathogens, taxonomic classification and management of each disease. Significant losses to clove production are reported due to sudden death and Sumatra disease. 3. Other diseases mentioned include leaf rot caused by Cylindrocladium quinquiseptatum, seedling wilt caused by various fungi, little leaf caused by a phytoplas

1. COLLEGE OFAGRICULTURAL TECHNOLOGY
(Affiliated to Tamil Nadu Agricultural University, Coimbatore-3)
Kullapuram (Po),ViaVaigai Dam, Theni-625 562
DISEASES OF CLOVE
STUDENT COURSE TEACHER
Miss. SUMITHRA.S Dr. PARTHASARATHY. S
ID NO : 2015021128 Asst.professor ( Plant pathology)

2. MAJOR DISEASES
DISEASES CAUSAL ORGANISMS
1. Leaf spot ,twig blight and flower
bud shedding
Colletotrichum gloeosporioides
2.Leaf rot Cylindrocladium quinquiseptatum
3.Sudden death Valsa eugeniae
4. Seedling wilt Rhizoctonia sp., fusarium sp.,
colletotrichum sp.,
5. Sumatra or die back Ralsonia syzygii, Endothia sp., and
phytopthora sp.,
6. Little leaf Phytoplasma

3. 7. Grey blight of clove Pestalotia palmarum
8. Leaf spot of clove Alternaria citri
9. Sooty mould of clove Phragmocapnius sp.
10. Alagal spot of clove Cephaleurous sp.
11. Black root rot Rosellinia pepo
12.Die back Cryphonectria cubensis

4. 1.Sudden death
Occurrence :
The clove crop of the zanzibar, on which the economy of
the islands is largerly based, and which provides nine-tenths of
the worlds supplies, is seriously threatened by the sudden-
death disease.
In 1950 , it was estimated that at least half of the clove trees
in zanzibar island had already been killed by this disease, and
that in island of Pemba for many years.

5. Sudden death
Pathogen :
Causal organism : Valsa eugeniae
( Nutman & F.M.Roberts )
Pathogenic character :
The perithecia are produced in large numbers.The
ascospores are formed during the rainy season are washed
down to the soil where the infect the roots.

6. Taxonomic position
• Kingdom : Fungi
• Phylum : Ascomycota
• Class : Sordariomycetes
• Order : Diaporthales
• Family : Valsaceae
• Genus : Valsa
• Species : Valsa eugeniae

7. Symptoms
• On mature trees, slight chlorosis occurs on the leaves which
results in a sudden and rapid leaf fall followed by wilting of
the plants.
• Complete death of the plants occur within a few days.Death of
the trees caused when the roots are unable to absorb water.
• Major fungal disease that affects the absorbing roots of mature
clove trees.

8. Management
• Cut off the branch cleanly below the infected area and paint
the cut surface with copper oxy chloride paste .
• There is no easy cure for sudden death disease, which is spread
by water borne spores,but clove trees affected are sometimes
injected with repeated injections of tetracyclin hydrochloride.

9. 2.Sumatra or die back
Occurrence :
Since the early 1960’s ,an apparently infectious
disease of cloves has been spreading throughout W.Sumatra,
one of the main clove producing areas of Indonesia.
Distribution:
Indonesia,Java,Srilanka,Brazil,SouthAfrica,
Taiwan,Philippines,Malaysia etc.,

10. LOSSES
• Sumatra disease is considered to be the single most important
threat to clove production in indonesia ,where cloves are used
in the manufacture of kretek cigarettes.clove provide an
important supplementary income to many small holders in
Indonesia .
• Annual losses in Indonesia were estimated to be $25 million in
1985.

11. Pathogen
Causal organism :
Ralstonia syzygii subsp. syzygii
Pathogenic character :
One of the xylem restricted or xylem limited bacteria,which
lives in the xylem cells or tracheary elements of plants.

12. Taxonomic position
• Kingdom : Bacteria
• Phylum : Proteobacteria
• Class : Betaproteobacteria
• Order : Burkholderiales
• Family : Burkholderiaceae
• Genus : Ralstonia
• Species : R.syzygii

13. Transmission
R.syzygii subsp syzygii is transmitted by insect vectors that
feed on xylem sap.
Primary spread :
Insects
1.Hindola fulva (sumatra)
2.Hindola striata (java)
Secondary spread:
Contaminated tools

14. Symptoms
• It is a bacterial disease that generally leads to the death of
clove trees within 3 years.
• It causes yellowing leaves that may wilt or drop from the tree.
• Greyish brown streaks may appear on new wood of diseased
clove trees.

15. Management
• Insecticide like aldicarb and carbofuran granules have
provided effective control.
• Antibiotic therapy has been used to extend the productive life
of infected trees but with some phytotoxicity .
• Inject an antibiotic called oxytetracyclin into trees to slow the
decline of infected clove trees.

16. 3.Leaf spot,twig blight and flower
shedding
Occurrence :
The disease was reported from kerala and when the flowers are
seriously affected there is heavy shedding and the losses are huge.
Symptoms:
Necrotic spots of variable size and shapes are noticed on the
leaves.
Severely affected leaves wither, droop down and dry up.

17. • In nursery seedlings die back symptoms are seen. Twigs are
infected as the symptoms extend from the leaves through
petioles.
• The affected branches stand without leaves or only with young
leaves at tips. Flower buds are attacked by spreading infection
from the twigs.
• Shedding of flower buds occurs during periods of heavy and
continuous rainfall.

18. Pathogen
Causal organism:
Colletotrichum gloeosporioides (Penz. &Sacc)
Pathogenic characters :
The mycelium is greyish white, thin and sparsely septate. Acervuli
are glabrous, rounded and elongated or irregular in shape with
setae.
Conidia are cylindrical with obtuse ends, one celled and are formed
on aseptate,hyaline.

19. Taxonomic position
• Kingdom : Fungi
• Phylum : Ascomycota
• Class : Sordariomycetes
• Order : Glomerellales
• Family : Glomerellaceae
• Genus : Colletotrichum
• Species : C.gloeosporioides

20. Favourable condition
• The organism has a wide host range.
• Heavy and continuous rainfall favour the infection and disease
spread.
Primary spread :
Dormant mycelium and ascospores from infected debris.
Secondary spread : Wind borne conidia

21. Management
• Destroy weed, clerodendron,growing in clove gardens as it
serves as the colleteral host.
• With the initiation of the disease spray the crop with bordeaux
(4:4:50) mixture or mancozeb(0.25%) and repeat at 14 days
interval particularly in rainy season.

22. 4. Leaf rot
Symptom:
• It is noticed in the nurseries as well as in the main field both at
young and mature stages.
• Infection starts as dark spots at the leaf margin and spreads
sometimes with no definite pattern.
• Rotting may be in the whole leaf or at the tip resulting in
defoliation.

23. Pathogen
Causal organism:
Cylindrocladium quinquiseptatum
Host plants :
Eucalyptus grandis
Eugenia maculata
Eugenia globulus
Pimenta dioica

24. Taxonomic position
• Kingdom : Fungi
• Phylum : Ascomycota
• Class : Sordariomycetes
• Order : Hypocreales
• Family : Nectriaceae
• Genus : Cylindrocladium
• Species :C.quinquiseptatum

25. Management
• Seedling and young plants can be sprayed with systemic
fungicides Carbendazim 0.1%.
• Prophylatic sprays with bordeaux mixture 1% also prevents
the disease.
• Removal of the affected seedlings.

26. 5.Seedling Wilt
Losses:
The mortality of seedlings due to seedling wilt in the nursery was
reported to range from 5-40 %.
Causal organism:
Cylindrocladium sp.,
Fusarium sp.,
Colletotrichum sp.,
Rhizoctonia sp.,and
Trichoderma sp

27. Symptoms
• Seedling wilt is found mainly in nurseries and causes five to
40% death of seedlings.
• Leaves of affected seedlings loose natural lustre, tend to droop
and ultimately die.
• The root system and collar region of the seedling show varying
degrees of, discolouration and decay.

28. Management
• Since the infected seedlings promote spread of the disease they
are to be removed and destroyed .
• The remaining seedlings should be treated with carbendazim
0.1% both as spray and soil drench. the nursery is drenched
with Copper oxychloride 0.25 %.
• Alternatively the foliage may be sprayed with bordeaux
mixture 1%.

29. 6.Little leaf
Symptoms:
• The affected trees exhibit symptoms of complete repression.
• The trunk shows numerous protuberances.
• The branches grow at acute angles with the trunk giving a
cone-shaped appearance to the tree.
• Leaves are reduced in size, internodes are short and primary
and secondary branches are arranged closer to each other.

30. • The disease also affects seedlings in the nursery.
• Presence of short internodes and clustering of small, crinckled
leaves is also observed.
Pathogen:
The disease is caused by Phytoplasma.
Management:
The disease can be kept under check by spraying tetracyclin.

31. 7.Black root rot
• Black root rot caused by Rosellinia pepo, a new disease of the
clove tree in Brazil.
Symptoms :
 Wilting, chlorosis and death, with dry leaves remaining
attached to the branches for sometimes.
 Especially on older plants,only the part of the tree exhibited
such symptoms,with leaves falling and leaving the plant
defoliated.