clubroot of cabbage...botany topic

1. Name : Anza Afzal Dar
Course Title : Diversity Of Plants
Course Code: BOT-101
Department : Zoology
UNIVERSITY OF
GUJRAT
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2. 20011514-055
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3. Content:
 Intoduction...............................4
 Distribution................................5
 History........................................6
 Economic Significance............8
 Symptoms..................................9
 Disease cycle............................12
 Pathogen....................................16
 Mode of Spread.........................18
 Disease Management...............20
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4. CLUBROOT OF
CABBAGE
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5. INTRODUCTION
Cabbage:
Cabbage is a member of
genus Brassica and
mustard family,
Cruciferaceae.
The sulphorane found in
cabbage may help to
protect from cancer.
Figure:
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6. DISTRIBUTION
 India,Nepal,China,West
Bengal,Canada,Bulgaria,Denmark and
Hongkong.
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7. HISTORY
 Historical reports of clubroot date back to the
13th century in Europe.
 In 19th century, a severe epidemic of clubroot
destroyed large proportions of the cabbage
crop in St. Petersburg.
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8. HISTORY
 The Russian scientist Mikhail
Woronin eventually identified the
cause of clubroot as a
“Plasmodiophorous organism”
in 1875, and gave it the name
Plasmodiophora brassicae.
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9. ECONOMIC SIGNIFICANCE
 Clubroot can be a reccurring problem, for
years because it is easily spread from plant to
plant.
 P. brassicae is able to infect 300 species of
cruciferous plants.
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10. SYMPTOMS
• Developing plants may not show any symptoms
but as the plants get older they will start to show
symptoms of chlorosis or yellowing.
• Wilting during hot days and stunted growth.
• The roots experience cell proliferation due to
increased auxin or growth hormone production.
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11. SYMPTOMS
 Gall formation occurs and restrict the
xylem tissue inhibiting efficient water
uptake by the plant.
 Galls appear like clubs or spindles on the
roots.
 The roots will rot and the plant will die
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12. CLUBROOT OFCABBAGE
©blog-yard-garden.com
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13.  In the spring, resting spores in the soil germinate
and produce zoospores and then these spores
swim and enter host plants through wounds or
root hairs.
 The plasmodium eventually divides and forms
secondary zoospores that are once again
released into the soil.
Disease Cycle of
Plasmodiophora brassicae
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14.  The secondary infection by the zoospores can
infect the first host or surrounding hosts.
 The secondary zoospores form a secondary
plasmodium that affects plant hormones to
cause swelling in root cells.
 These cells turn into galls or “ club “.
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15. Contd.
 The secondary plasmodium forms the
overwintering resting spores which
get released into the soil as the club
rot and disintegrate.
 These resting spores can live in soil
for upto 20 years while they wait for a
root tip to come in close proximity for
them to infect.
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16. ©canolacouncil.org
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17. P
ATHOGEN
 Obligate parasite.
 Plasmodium shaped body.
 Can survive in soil as resting spores for many
years.
 Produce primary and secondary zoospores.
Zoospores are biflagellate. 20011514-055
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18. MODE OFSPREAD
 Primary:Restingspores
 Secondary: Zoospores
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19. Resting spores: Zoospores:
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20. FAVOURABLE CONDITION
m
oist
 It prefers warmer temperature and
conditions.
 Soil temperature between 20 - 24°C.
 pH less than 6.5.
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21. INTEGRATED DISEASE
MANAGEMENT
 Seedlings can carry the pathogen so the use of
disease free seedlings is therefore very important.
to reduce the
 Remove the affected roots pathogen
population in the soil.
 Practice long term crop rotation with potato, tomato,
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22.  Incorporate lime into the field at the rate of
2.5t/ha two weeks before transplanting .
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