Studies on Black Rot (Xanthomonas campestris pv. compestris (Pammel) Dowson) of Cabbage (Brassica Oleracea var. Capitata) Under South gujarat condition
Loading...
Date
2000-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Plant Pathology Department, N. M. College of Agriculture Gujarat Agricultural University
Abstract
Cabbage (Brassica oleracea var. Capitata) is one of the
important cole crops grown as winter vegetable in Gujarat. Among
different diseases, black rot of cabbage, caused by Xanthomonas
campestris pv. campestris (Pammel) lJowson, is one of the most
destructive diseases
throughout South
Gujarat. Considering the
seriousness of the problem, the present studies were carried out to
generate more infOllIlation for developing suitable control measures.
The isolation from infected cabbage leaves revealed the
association of Xanthomonas sp. with black rot. The pathogenicity of
Xanthomonas sp. was proved by artificial inoculation methods viz.,
tooth brush injury, pin pricking, carborundum powder injury and
spraying of inoculum without injury with positive results. Thepathogenicity was confirmed upon detached leaves as well as in pot
culture.
Results of morphological, cultural and biochemical tests
tallied with the reports of the earlier workers. Upon nutrient agar
medium, pathogen produces creamy yellow, smooth, circular, bright
raised colonies, while upon tetrazolium, fiat, dark brown, circular and
smooth colonies. The pathogen is recorded for the first time in Gujarat.
Among the various solid media tested, nutrient agar, SX
agar and yeast glucose chalk agar were proved best for studying the
growth and colony characters of Xanthomonas
campestris pv.
campestris.
Fructose and sucrose were proved to be better while starch,
galactose, mannitol, lactose and glucose were inhibitory sources of
carbon. Di-ammonium hydrogen orthophosphate and potassium nitrate
accelerated the growth while ammonium oxalate, sodium nitrate,
arrunonium nitrate, urea and arrunonium sulphate inhibited the growth
of the bacterium. Thermal death point of the pathogenic isolate was
52°C.
Host range studies comprising of eight different plant and
weed
species
belonging
to
different
families
indicated
that
X campestris pv. campestris readily infected three species namely
cauliflower, mustard and radish belonging to family €ruciferae, which
are the known hosts of this bacterium while. the leaves of brahmi
showed the epiphytic survival of X campestris pv. campestris.
Seed borne nature of the bacterium was detected by using
moist blotter paper technique. Seed lots of susceptible variety'Golden Acre' and 'Pride of India' consisted more number of infected
seeds than other varieties tested.
The phyto-extracts of twenty two plant species were
screened in vitro by paper disc method against X.
campestris
pv.campestris, gando baval proved strongly inhibitory followed by
garlic bulb, sankal chain, turmeric rhizome, black basil and eucalyptus.
In vitro screening of chemicals were carried out by the
paper disc method, indicated that Streptocycline and MEMC (Emisan)
were highly bactericidal to X campestris pv. campestris followed by
Agrimycin, Mercuric chloride, Zirum (Cuman-L), Captafol (Foltaf) and
Mancozeb (Dithane M-45).
Among the fungicides and/or antibiotic and hot water
treatment tested for their efficacy in eliminating seed borne infection of
the bacterium, hot water (50°C for 30 minutes), Streptocycline
(0.01 per cent) and Mercuric chloride (0.01 per cent) were found
comparatively more effective. Inoculation of seeds with the culture of
X campestris pv. campestris reduced their gellnination but, when the
inoculated seeds were tested with Streptocycline and hot water, the
ee7' OO)
seed germination was improved, maximum seed genninatiol'.A was in
Streptocycline (0.01 per cent).
Among six evaluated cabbage varieties against the black
rot, Hybrid NS-27, Hybrid NS-22 and Midorimaru were resistant,
Express was moderately resistant while Golden Acre and Pride of India
were highly susceptible under both natural and artificial inoculated
conditions.
Description
Keywords
null
Citation
PRADEEP SHRMA_32615