Consider the following four measures (A-D) that could be taken to successfully grow chick pea in an area where bacterial blight disease is common
(A) spray with Bordeaux mixture
(B) control of the insect vector of the disease pathogen
(C) use of only disease-free seeds
(D) use of varieties resistant to the disease
Which two of the above measures can control the disease?
(1) B and C
(2) A and B
(3) C and D
(4) B and D
(3) Bacterial blight of chick pea (Cicer arietinum) is caused by bacterium Xanthomonas campestris. The ejected tissues collapse and are digested by bacteria. Rapid spread of bacterial infection occurs through vascular strand. The stems and leaves of infected plant give blighted or burnt up appearance. Control measures include rogueing; 3-year crop rotation, disease free seeds, spray of copper fungicides and antibiotics besides showing disease resistant varieties.
Bordeaux mixture is most common fungicide. It was first discovered by Millardet in 1882 at university of BOrdeaux France to control downy mildew of grapes. It is prepared by mixing copper sulphate, lime and water in the ration of 4 : 4 : 50