Red Rot of Sugarcane

Red Rot of Sugarcane:-

Pathogen:- Glomerella tucumanensis. (Older name = Colletotrichum falcatum)

Symptoms:-            

> The affected canes exhibit leaf colour change, from green to orange and then to yellow in the third or fourth leaf. Then the leaves start drying from bottom to top.

> If the fungal spores enter the leaf sheath through the leaf midrib, then reddish spots can be seen on the back side of the leaf midrib also.

> The external symptoms appear only after16 - 21 days after infection and drying of entire cane takes another 10 days time.

> When the affected cane is split opened, the inner region is reddish in colour with intermittent white tinges across the cane length.

> Sometimes, the pith inside the cane is filled with blackish brown liquid and exhibited alchohol odour.

Management:-

i. Cultural method:- 

> The best way to control red rot is to select setts for planting from healthy plants in a disease- free area.

> The red rot affected field must be rotated with rice for one season and other crops for two seasons.

> Growing of recommended resistant and moderately resistant varieties viz., Co 86032,  Co 86249, CoSi 95071, CoG 93076, CoC 22, CoSi 6 and CoG 5.

ii. Physical method:-

> Removal of the affected clumps at an early stage and soil drenching with  Carbendazim 50 WP (1 gm in 1 litre of water).

> The cut ends and entire setts should be dipped in a fungicide solution, such as one per cent Bordeaux mixture.

> If the disease is noticed in the field, the leaves and canes should be collected and destroyed by burning.

iii. Chemical method:-

> Adopt sett treatment with Carbendazim before planting (Carbendazim 50 WP (0.5 gm in 1 litre of water) or Carbendazim 25 DS (1gm in 1 litre of water) along with 2.5 kg of Urea in 250 litre of water.

> Use fungitoxic chemicals like Bavistan, Benomyl, Topsin and Aretan at 0.1 per cent for 18 min. at 52ºC for dipping setts which gave almost complete elimination of rot infection.