Consider the following four measures (i-iv) that could be taken to successfully grow chickpea in an area where bacterial blight disease is common: (i) Spray with Bordeaux mixture (ii) Control of the insect vector of the disease pathogen (iii) Use of only disease-free seeds (iv) Use of varieties resistant to the disease Which two of the above measures can control the disease?
- (i) and (ii)
- (i) and (iv)
- (ii) and (iii)
- (iii) and (iv)
Answer
(2) (i) and (iv)
Solution
Bacterial blight is a bacterial disease (caused by Xanthomonas); it is not spread by an insect vector. (ii) is not a control measure.
In an area where the disease is common, the pathogen is already present in the field, so using only disease-free seeds does not by itself control the disease. (iii) is not enough.
Bordeaux mixture is a copper-based spray; copper sprays act on bacteria as well as fungi and protect the foliage from blight. (i) controls the disease.
As per NCERT, growing disease-resistant varieties is the most effective way to control plant diseases (e.g., Pusa Komal, a cowpea variety resistant to bacterial blight). (iv) controls the disease.
Measures (i) and (iv) control the disease.
Answer: (2)