Kernel bunt of wheat
C/O: Tilletia indica (Synonym: Nevossia indica)
Symptoms:
- Only a few kernels of some wheat heads are infected, and usually only a portion of an infected kernel is replaced with fungal sorus.
- Black, dusty-appearing teliospores give this group of organisms the name “smut.
- The infection is usually confined to a few grains in the spike with irregular arrangement.
- In some cases the infection may spread to only a part of the grains.
- In severe cases, the grain is reduced to black shiny sac of teliospores.
- As the grains mature the outer glumes spread and the inner glumes expand, exposing the bunted grains.
- The bunt balls are first enclosed by the pericarp but when it bursts the masses of bunt spores are exposed.
- Symptoms are most readily detected on seed after harvest.
The bunt affected plants emits a foul smell which is mainly due to the presence of Trimethyl amine.
Etiology:
- Teliospores are smooth walled and require a long resting period.
- sickle shaped (allantoid) secondary sporidia are produce which help in the dispersal of karnal
Favorable condition:
- At flowering stage of plant.
- Cloudiness or rainfall during anthesis favours disease development in susceptible host varieties.
- Tempr 20-25o
- Relative humidity: more than 85%.
Survive and spread:
- Soil and Seed born disease.
- Survive: teliospores and teliosporogenous hyphae present in kernel and soil.
- Spread: sickle shaped (allantoid) secondary sporidia are produced which help in the dispersal of karnal bunt.
Management:
- Adjust date of sowing
- Intercropping with Gram or Lentil
- Seed treatment with copper carbonate or Thiram@3g/kg seed or Carbendazim (bavistin) @2.5 g/kg of seed
- Spray with carbendazim@0.1% or carboxin@0.2% or Mancozeb@0.25% or bitertano