Abstract
Streptomycin would be diluted in the course of growth of the developing leaf but it remained over 5 weeks in the fully developed leaf. When applied to the stem, it moved to the phloem and pith, reaching to the next leaf above the place of absorption, and later proceeded gradually to the upper leaves. It could not be traced in the xylem. It could not traverse the midrib and move from one longitudinal half to the other, neither did it move from the basal to the apical part of the leaf or vice versa.
When inoculation with Pseudomonas tabaci was carried out one day after spraying the leaves with 220, 110 and 73mcg/ml water solutions of streptomycin, the disease was found to be under complete control even 10 days after inoculation. A concentration of about 110mcg/ml can be recommended. The yellow halo around the spots of infection will turn green when sprayed with such a solution. In the case of Ps. solanacearum, 5 days after inoculation the pathogenic organism was present due to the dilution of streptomycin in the tissue, which should be controlled by making the repeated spraying.
