Turmeric is vulnerable to various kinds of diseases and pests. To avoid disease spread and minimise damage, it is critical to observe turmeric plants on a frequent basis and to respond quickly if any indications of illness are seen. The following are some of the most common diseases that can harm turmeric plants.
Soft Rot or Rhizome Rot
This disease result in rotting of the rhizome (the underground part of the plant that we use). The symptom starts as progressive drying of leaves along the margin. The collar region of the pseudo stem becomes water-soaked, soft and rotten. This ultimately results in collapse of the tillers and decay of rhizomes. The tillers come out with slight pull and rotten collar region of the tiller and the rhizome emit foul smell. Affected rhizome becomes soft, watery and rotted. The colour of rhizome changes from bright orange to shades of brown.(C.O. pythium graminicolum, p. aphanidermatum).
Management
Select healthy seed rhizomes from disease free areas. Use healthy rhizomes collected from disease free fields for planting. Treat the seed rhizomes with Metalaxyl + Mancozeb 8 + 64 wp (2 gram /litre of water) or Mancozeb 75 wp (3 gram/ litre of water) for 30 minutes prior to storage and at the time of sowing.
Ensure proper drainage in the field. Prophylactic soil drenching with copper oxychloride 50 wp ( 2 gram/litre of water) or Copper hydroxide 50 wp (1.5 gram/ litre of water) or 1% Bordeaux mixture or Cheshunt compound before south west monsoon( May ,June) then at monthly interval for 2-3 time reduced the disease incidence. When the disease incidence is noted in the field, dig out the affected plants and drench the beds with Cheshunt compound or Bordeaux mixture (1%)or Mancozeb 75 wp (3gram/litre of water). In diseased field, spray drench the bed with Metalaxyl + Mancozeb 8 + 64 wp ( 2 gram/litre of water) or potassium phosphonate 40 sc ( 4 ml)+ Hexaconazole 5 EC (1ml) in one litre of water.
Bacterial Wild
When turmeric plant is affected with bacterial wild disease, all branches will wilt at about the same time. When the stem of a wilted plant is cut across, the pith has a darkened, water-soaked appearance. The first conspicuous symptom is mild drooping and curling of leaf margins of the lower leaves which spread upwards. Yellowing starts from the lowermost leaves and gradually progresses to the upper leaves.
In the advanced stage, the plants exhibit severe yellowing and wilting symptoms. Bacterial Wilt spreads through contaminated soil, water, and infected plant material. It can be particularly problematic in regions with warm and humid conditions.
Management
The seed rhizomes may be treated with streptocycline (5 gram /10 litre of water) for 30 minutes and shade dried before planting. Ensure proper drainage in the field. Select seed rhizomes from disease free areas.
When incidence of rhizome rot is noted in the field, dig out the affected plants and drench the beds with Cheshunt compound or Bordeaux mixture (1%). Inoculation with native pseudomonas fluorescens (20 gram/ litre of water) at the time of planting is recommended as a biocontrol measure. Keep bleaching powder in sac at the entry point of irrigation water to disinfect it.