STUDIES ON BACTERIAL SPOT OF BELL PEPPER (Capsicum annuum L.) CAUSED BY Xanthomonas campestris pv. vesicatoria (Doidge) Dye
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Date
2009
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Publisher
UHF,NAUNI,SOLAN
Abstract
ABSTRACT
Bacterial spot (Xanthomonas campestris pv. vesicatoria (Doidge) Dye) is an
important disease of bell pepper in mid hills of Himachal Pradesh. Present investigations
were undertaken with an objective to study the occurrence of the disease, role of abiotic
environmental factors in disease development and to devise suitable disease management
strategies. The disease was found to occur in moderate to severe form in different bell
pepper growing areas of Solan, Shimla and Sirmour districts of Himachal Pradesh. Based
on morphological, cultural and biochemical characters, the identity of the pathogen was
confirmed to be Xanthomonas campestris pv. vesicatoria (Doidge) Dye. Optimum growth
of the pathogen was obtained at 30o C and pH 7.0. Nutrient sodium chloride broth
favoured maximum growth of the bacterium. Moderate temperatures (25 + 1o C) coupled
with high relative humidity (80%) were found to favour the disease development. Two
lines viz., Feroz and EC-57997 were found moderately resistant while eight lines
viz., Selection 17-1-2, Kanauri, SP-628, Midway, EC-57996, Navgaon Collection,
Nishant and KTCPH-7 exhibited moderately susceptible reaction under natural
epiphytotic conditions. Among five biocontrol agents evaluated, only Pseudomonas
fluorescens inhibited the growth of bacterium under in vitro conditions. Aqueous extracts
of Allium sativum and Curcuma longa inhibited the growth of the bacterium under in vitro
conditions. Foliar sprays of combination of streptomycin sulphate (0.01%) + copper
oxychloride (0.25%) and streptomycin sulphate (0.01%) alone resulted in minimum
disease severity and maximum fruit yield.
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Keywords
economics, biological phenomena, resins, productivity, technological changes, exhibitions, developmental stages, marketing, biological development, selection