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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) 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?
A
(iii) and (iv)
B
(i) and (iv)
C
(ii) and (iii)
D
(i) and (ii)
Detailed Solution
Bacterial blight is caused by a bacterium, and it is mainly a seed-borne disease.
(iii) Use of only disease-free seeds removes the primary source of infection, so it controls the disease.
(iv) Use of varieties resistant to the disease is the most effective and economical measure, because the pathogen cannot establish itself on a resistant host.
(i) Bordeaux mixture (copper sulphate + lime) is a fungicide. It is used against fungal diseases and is not the measure for a bacterial blight.
(ii) The blight bacterium is not spread by an insect vector; it spreads through infected seed, rain splash and plant debris, so vector control does not help.
So the two measures that can control the disease are (iii) and (iv).
(iii) Use of only disease-free seeds removes the primary source of infection, so it controls the disease.
(iv) Use of varieties resistant to the disease is the most effective and economical measure, because the pathogen cannot establish itself on a resistant host.
(i) Bordeaux mixture (copper sulphate + lime) is a fungicide. It is used against fungal diseases and is not the measure for a bacterial blight.
(ii) The blight bacterium is not spread by an insect vector; it spreads through infected seed, rain splash and plant debris, so vector control does not help.
So the two measures that can control the disease are (iii) and (iv).