Common bunt of wheat

C/O: Tilletia tritici (low smut), Tilletia laevis (high bunt)

• Also called hill bunt, stinking bunt cover smut of wheat (due to its sori).

Symptoms:

• Visible at heading satge.
• Both species produce different symptoms T.caries(low bunt) affected culms are shorter than the normal and the plants affected by T.foetida(high bunt) are more often higher than the normal ones.
• At the time of flowering hyphae concentrate in the inflorescence and spikelet’s and transforming the ovary into smut sorus of dark green color with masses of chlamydospores.
• After heading, the spikelets of infected plants tend to flare-out (expansion of seed due to filled of teliospore) and take on a greasy, off-green color.
• Infected heads may have shorter awns, or even no awns.
• Slightly discolored grains which are full of black powder and gives foul smell.
• Mass of black spores that smell like rotting fish due to trimethylamine.

Dwarf bunt :

C/O: Tilletia controversa

• infected wheat spike, with glumes removed to expose fungal sori (bunt balls).

Etiology of hill bunt:

• Two species are distinguished based on the morphology of the bunt spores.
• Teliospores of  tritici have ridges on their walls which gives them a “warty” appearance
• Teliospores of  laevishave smooth spore walls.

Favorable condition:

• Tempr: 5-15^oc
• Cool environment and soil .
• RH: >75%

Survive and spread:

• Survive: teliospore as resting spore of common bunt present in infected seed or infected seed present in soil during harvest acts as primary inoculum.
• Spread: contaminate other seed being harvested or are spread by the wind to the soil surface, later to be incorporated into the soil mass during cultivation.

Disease cycle:

• Systemic disease

• Seed borne disease

Management:

• Adjust date of sowing
• Sowing at soil tempr above 20^oc which inhibit teliospore germination.
• 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 bitertanol.