Investigations on black rot of cauliflower (Brassica oleracea var. botrytis L.) caused by Xanthomonas campestris pv. campestris (Pammel) Dowson
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Date
2008
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Publisher
MPUAT, Udaipur
Abstract
Bacterial black rot is a major disease of cauliflower (Brassica oleracea var. botrytis
L.). The disease has been observed in all cauliflower growing areas of the state including
Udaipur.
The disease initially appeared as small water soaked lesions on the leaf periphery,
which later on increased in size. The pathogen produced V-shaped chlorotic lesions on the
leaf margins upon invasion through hydathodes.
Morphological, cultural and biochemical characteristics were studied. The bacterium
appeared as straight, capsulated rods with single polar flagellum under the oil immersion
objective of compound microscope. It was identified as Xanthomonas campestris pv.
campestris.
Best infection was obtained by carborundum abrasion method. The disease was
favoured by temperature between 30-330c and relative humidity above 82-89 per cent. High
and low temperatures and dry weather were found adverse for its development.
The bacterium, X. c. pv. campestris causing black rot reduced the quantity of
chlorophyll, protein and phenol in disease affected plant leaves.
Under climatic conditions of Udaipur none of the varieties were found tolerant
against bacterial black rot of cauliflower. However, Pusa deepali and Kartiki exhibited
moderatly tolerant.
Streptocycline (500 ppm) gave maximum inhibition of the bacterial growth in vitro.
Out of four plant extracts, Neem and Garlic extract inhibited the growth of X. c. pv.
campestris, effectively.
Streptocycline (250 ppm) was found most effective in seed germination (66.67 per
cent) against X. c. pv. campestris and in case of plant extract Neem leaf and Garlic bulb
extract was found most effective.
Description
Investigations on black rot of cauliflower (Brassica oleracea var. botrytis L.) caused by Xanthomonas campestris pv. campestris (Pammel) Dowson
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Citation
Bairwa and Mali, 2008