THE CROP DISEASES OF SIKKIM HIMALAYAS

CROP: GINGER
Scientific Name Zingiber officinale Rosc.
Local Name Adhuwa
Family Zingiberaceae
State/World wide Sikkim, Darjeeling, Arunachal Pradesh, Asia and South East Asia
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Common Name of Disease: 1. SOFT ROT
Local Name of Disease -Adua Kuhiney Bimar
Causal Organism -Pythium aphanidermatum
Distribution of Disease in Sikkim

-Disease incidence in maximum in high rainfall areas of North, East, and some areas of West Sikkim and less in South Sikkim
Disease Incidence -Low to medium
Site of Infection

- Color region of the pseudostem, leaves and rhizome.
Dissemination of the Disease - It is a seed-borne and soil borne disease.

Symptoms
Yellowing of lower leaves progressing upwards. Pseudostem comes off easily with a gentle pull. Disease is noticed during July-August. Pythium in association with maggots, viz. Mimegralla sp. has frequently been noticed in the affected plant parts.Favourable environmental condition for disease:Water stagnation in the field during rainy season.Hot and humid weather condition favours the disease incidence. Injury caused to the rhizome during mau extraction makes the plant susceptible to the disease.
Plant Protection Measures
Seed should be selected from a diseased free source. Fresh land free from disease inoculums should be selected based on previous history. Crop rotation of 3-4 years with non leguminous crops should be followed to suppress pathogen inoculums in the soil.Planting should be done on raised bed of small size with proper drainage. Thick mulching should be provided to check weed growth and to conserve moisture. FYM should be well decomposed to avoid white grub infestation. Planting of ginger should be done on sloppy land to avoid water stagnation. Seed and FYM can be treated with Trichoderma spp.+Pseudomonas florescens before sowing to control disease. Frequent monitoring of the field is very important in order to check the disease from spreading. If one or two plants look infected go for uprooting and dispose off after boiling them in hot water to avoid contaminating the soil or water. Then treat the spot with 5% cow urine and Trichoderma spp.to check the spreading of pathogen. Use Bordeaux mixture or Cupper Oxychloride 2.5g/litre water to control the disease.Brief history of the disease: Rhizome rot or Soft rot of ginger, a serious menace to the cultivation of the crop, is reported from all the ginger growing areas including Bangladesh, Sri Lanka, Fiji, Japan, India and Taiwan. The disease was first reported by Butler from Surat (Gujarat). Subramanian described it from Pusa (Bihar). Besides causing damage in field, a large portion of the seed rhizomes is also destroyed in storage. The seed rhizomes are, as a rule, stored in pits soon after harvest and taken out for planting after a lapse of over 5 months. It has been found that 50-90% of stored rhizomes exhibits considerable shrinkage and rot by the time the pit is opened.
Mode of Transmission
Disease is transmitted to a healthy plot through infected planting material, mechanical transmission through human activities. Drainage / run off water flowing across the diseased plot also carries fungal spores to a non-contaminated plot at the lower elevation.
Life cycle of Organism
The zoospore of pathogen lie scattered in the field and serve as inoculum for next crop.

Bioinformatics Sub- DISC, SSCS&T