The document discusses mango dieback caused by the fungus Lasiodiplodia theobromae. It affects mango crops in India, Nepal, China, and other countries. The fungus overwinters in pycnidia on diseased wood and releases spores during rainy weather which infect wounds on trees, causing cankers and dieback. Management includes pruning outside of rainy seasons, minimizing wounds, and applying fungicide to pruned areas to control the spread of the disease.

1. COLLEGE OF AGRICULTURAL TECHNOLOGY
(Affiliated to Tamil Nadu Agricultural University, Coimbatore-3)
Kullapuram (Po),ViaVaigai Dam, Theni-625 562
MANGO DIEBACK
Student
Afrin J.
Course teacher
Dr. S. Parthasarathy
Assistant Professor (Plant
Pathology)

2. DISTRIBUTION
• India, Nepal, China, West Bengal, Canada,
Bulgaria and Pakistan.

3. HISTORY
• Historical reports of Mango dieback go back to
1970’s.
• In 19th century, a severe epidemic of dieback
destroyed large proportions of the mango crop
in Pakistan.

4. ECONOMIC SIGNIFICANCE
• Dieback can be a recurring problem, for years
because it is easily spread from plant to plant.
• Mango dieback is able to affect 40% of the yield
loss.

5. SYMPTOMS
• In affected plants, twigs die from the tip from
the tip back into old wood, giving a scorched
appearance to the limb.
• The affected leaf turns brown and its margins
roll upwards. Leaves scorch and fall, leaving a
dead branch – DIEBACK.

6. • The infected plants show abundant gum
secretion from branches, stem and main
trunk.
• Under severe condition, the outer wood of a
branch cracks and splits and excudes a
yellow to brown, gum like substances –
GUMMOSIS.

7. DIEBACK OF MANGO
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8. SYSTEMIC POSITION
• Kingdom : Fungi
• Division : Ascomycota
• Class : Dothideomycetes
• Order : Botryosphaeriales
• Family : Botryosphaeriaceae
• Genus : Lasiodiplodia
• Species : L. theobromae

9. DISEASE CYCLE OF
Lasiodiplodia theobromae
• The fungus over winters as pycnidia on the
outside of diseased wood.
• The pycnidia produces and releases two-celled,
dark brown, straited conidia.
• The conidia are then dispersed by wind and rain
splash, spreading the fungi to other parts and
from one part of plant to another.

10. • Disease develops when conidia land on
freshly cut or damaged wood.
• The conidia germinate the tissue of the wood
system and start causing damage to the
vascular system.

11. • Cankers begin to form around the initial
infection point and eventually complete
damage of the vascular system causes necrosis
and dieback of the wood.
• In some instances, pseudothecia form on the
outside of cankers and produce ascospores
which are then dispersed like conidia and
infect surrounding wounds.

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13. PATHOGEN
• The fungus over winters as pycnidia on the outside
of diseased wood.
• The pycnidia produces and releases two-celled, dark
brown, straited conidia.
• In some instances, pesudothecia form on the outside
of cankers and produce ascospores which are then
dispersed like conidia and infect surrounding
wounds.

14. CONIDIA
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15. FAVOURABLE CONDITION
• It prefers rainy season.
• Avoid watery condition.

16. MANAGEMENT
• Avoid pruning during wet weather (spores of
Botryosphaeriaceae fungi are released upto 2
hours after rain.
• Minimize number and size of pruning wounds.
• Cuts should be made at an angle to allow water
to drain from the wood surface.

17. • Prune early in the season when spore
production is low or late in the season when
wounds are less susceptible and heal more
rapidly.
• Apply Copper Oxy Chloride 3% on the pruned
area.