Dry root rot of Chickpea
The climatic variables; temperature, rainfall pattern and its distribution have become more erratic under the changing scenario of climate. Climate change has adverse impacts on agriculture. These changes have also affected the reproduction, spread and severity of many plant pathogens. Thus the previously categorized minor diseases have become major threats in many crops. In chickpea drastic shift of diseases have been recorded throughout the major chickpea growing regions in India and elsewhere. Dry root rot (DRR) caused by Rhizoctonia bataticola (Taub.) Butler [Pycnidial stage: Macrophomina phaseolina (Tassi) Goid] was found as a potentially emerging constraint to chickpea production. The disease generally appears during reproductive phase of the crop. The disease may also appear at seedling stage, however, the susceptibility of the plant increases with age. The disease generally appears when day temperature is more than 300C. The symptoms/diagnosis of the disease and its control/preventive measures are presented here.
- Drying of the plants appears suddenly and affected plants are scattered in the field.
- Affected plants are usually straw coloured, in some cases the lower leaves and stems show a brown colour.
- Drooping of top most petioles and leaflets is observed.
- The lower portion of the tap root usually remains in the soil when the plant is uprooted.
- The tap root is black, rotten and devoid of most of the lateral and fine roots.
- The dead root is quite brittle and shows shredding of the bark.
- Dark minute sclerotial bodies can be seen on the exposed roots or inside the base of the stem.
- When the dry stem of the collar region is split vertically, mycelium or minute sclerotia can be seen in the pith.
- Selection of Tolerant varieties
- Seed treatment: Tebuconozole, Carboxin+Thiram, Captan, Thiram or cabendazim @ 2g. per kg of seeds. Or bioagents like Trichoderma harzianum or Trichoderma viridae, @ 6g. per kg of seeds.
- Cultural practices: i. Deep ploughing during summer
ii. Intercropping with fenugreek
iii. Soil solarization
iv. Cultivation of chickpea in raised bed and furrow method
4. Crop rotation: Crop rotation with cereals preferably with sorghum.