1Division of Plant Pathology, Central Potato Research Institute, Shimla, (H.P), India.
2Department of Plant Pathology & Protection, National Botanical Research Institute, Lucknow-226 001, (U.P.), India.
Interaction of systemic chemicals with Pseudomonas solanacearum EF Smith and its specific phage (Psp13) was studied. When host-phage complex was plated with different concentrations (5, 10 and 20 ppm except vitavzx and Benlate-100, 150 and 200 ppm) of the chemicals, the per cent plaque formation increased from 1.4 to 8.5 per cent at lower concentrations with 2 chloroethyle phosporic acid (Ethrel), 2,4 Dichloro phenoxy acitic acid (2,4-D, Sodium Salt) and Kasugamyc in hydrochloride whereas 30–40 per cent reduction was observed with vitavax and Benlatein contrast of 2,4-D and Ethrel. Plaque formation was inhibited totally with Streptocycline, Streptomycin, and chloramphenicol. The plaque size was not affected with both the growth regulators viz. Ethrel and 2,4-D at any concentrations tried. When the bacterium and its phage were treated with Ethrel and 2,4-D separately, the plaque size either remained constant or increased while the reduction in plaque appearance varied from 7.2–20 per cent. The bacterial cells treated with growth regulators for 30 min, When inoculated to potato plants (six leaf stage) by root injury produced typical wilting within 20 days.
