Question

Bankane disease is caused by:
(a) Fungal toxin
(b) Growth hormone released by fungal infection
(c) Change in photoperiod
(d) Inadequate nutrients

Answer 1

Hint: This disease was reported 1st in Japan in 1898. Then it has been reported from China , Italy , Uganda , India and Pakistan. This disease has recently been observed on Paddy in Pakistan.

Complete step by step answer:
Bankane disease means ‘foolish seedling’ because infected plants elongate too rapidly and are unable to support themselves and they are also male sterile
Symptoms in nursery:
- The disease affects seedling in the nursery.
- Seedlings appear whitish pale and weaker.
- Seedlings appear taller than healthy one.
- In this case of severe infection, tips of seedling show symptoms of wilting.
- Infected plants by this disease die in nursery or soon after transplantation.
So, the correct answer is, ‘(b) Growth hormone released by fungal infection.’

Additional Information:
Symptoms in field:
- Infected plants appear tall and flower earlier.
- Early flowering is due to hormones like gibberellins.
- Some plants show symptoms of fungal infection in the collar region.
- Plants die in about 2- 6 weeks after infection.
- In few cases plants show stunted growth due to mycotoxins like fusaric acid.
- There is variation in symptoms of aerial parts.
- Due to variations in symptoms identification of diseased plants becomes difficult.
- Roots emerge even from the second and third node.
- Roots of these plants also branch profusely as compared to healthy one.
- Pinkish growth of fungus also visible at the base of plants and within spilt nodes.
Disease cycle
- The pathogens of bankane disease live both in seed and in soil.
- On seed these plants are frequently observed and also identified in soil.

Note:
Epidemiology
- The fungus have a wide range of temperatures for optimum growth which is between 30 - 35 C.
- It grows best in moisture.
- Excess use of nitrogen fertilizer predisposes the plant to the attack of pathogens.
Control
- The seeds must be collected from areas free from disease.
- The seeds should be stored under dry conditions.
- The irrigation water should not be allowed to go from infected fields to the healthy ones.
- The seeds are dressed by fungicides like benlate or topsin.