|
THE CROP DISEASES OF SIKKIM
HIMALAYAS |
|
CROP:
MANDARIN ORANGE
|
|
Scientific Name |
Citrus reticulate |
|
State/World wide |
Sikkim, Assam, Meghalaya, Nagpur, Darjeeling Nepal, Bhutan
|
|
|
|
|
|
|
Common Name of Disease:
|
1. CITRUS DIE-BACK |
|
Local Name of Disease |
- |
|
Causal Organism |
-Colletotrichum gloeosporioides |
|
Distribution of Disease in Sikkim
|
-Disease has been reported from
the four districts of Sikkim.
|
|
Disease Incidence |
-Moderate to High |
|
|
Site of Infection |
-
The leaves become yellow and fall with
the beginning of summer and die-back of twig starts leading
to drying of branches and declining –death of trees.
|
|
Dissemination of the Disease |
- It is a seed-borne and
soil borne disease. |
Symptoms
Symptoms first appear
on older leaves. The mid rib and veins
become yellow and later turn into orange
yellow. Molting of leaves take place. The
new leaves are swollen in shape and on
touching some bristles are felt. Following
year even the interveinal areas become
chlorotic. Plant growth is stunted and
appears bushy.Gradually the whole plant dies
from top to bottom.
|
Favourable environmental condition for
disease
Presence of hard pan at the root
growing zone (rhizosphere), preventing root
penetration into the soil thereby hindering
nutrient uptake by the roots for proper
growth and development.Growing citrus too
near to the edge of the terraces. Causing
mechanical injuries to the roots during
tillage for intercropping. Grazing cattle in
the orange orchard. Citrus die-back is not a
disease but a disease syndrome i.e.,
combined affect of both biotic and abiotic
factors.
|
Mode of
Transmission
Transmission of disease take place through
infected planting materials, mechanically
through contaminated pruning knife and
sometimes from soil borne pathogen.
|
Life cycle of
Organism -
|
Brief
history of the disease -
|
|
| Bioinformatics Sub- DISC, SSCS&T |
|
|