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 MANDARIN ORANGE Citrus Die - Back

Name of Crop    MANDARIN ORANGE
Scientific Name    Citrus reticulate
Local Name    Santra
Family    Rutaceae
Distribution state/World wide    Sikkim, Assam, Meghalaya, Nagpur, Darjeeling Nepal, Bhutan
Common Name of Disease    CITRUS DIE-BACK
Local Name of Disease     CITRUS DIE-BACK
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 t                                          ouching 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 enviromental 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