Diseases of radish

This is about the diseases of Radish.

1. Diseases of Radish




ANJALI
Bsc.Hons.Agriculture
3rd Year

2. Diseases of Radish (Raphanus
sativus)
1.Alternaria leaf
spot
2.Downy
milldew

3. Alternaria Leaf spot
►The disease appears, visually in December and
reaches is maximum towards the end of
January and beginnings of February in the
northern part of our country.
►The loss of yield due to disease is vary from
9-28% depending on variety.

4. •Symptoms
►The symptoms may occur on leaves.
►Leaf spots are spherical to elliptical,
raised and yellow in appearance. They
contain characteristic concentric rings
and soon dry in their central region, which
may drop out.

5. Symp…..

6. •Causal Organism
Kingdom : Fungi
Division : Eumycota
Sub-division : Deuteromycotina
Class : Hyphomycetes
Order : Hyphomycetales (Moniliales)
Family : Dematiacea
Genus : Alternaria
Species : raphani

7. Causal Org…..
►The mycillium is septate, light coloured profusely
branched and inter- and intracellular. They mature and
produce conidiophores which bear conidia.
►The conidiophores are generally producing groups from
a stroma. Its conidia are septate, producing singally or
in short chains, short beaked measure 75-115 × 14-18
micron on maturity.

8. •Disease Cycle

9. •Predisposing Factors
►Moist and foggy weather is favorable
environmental condition for conidia
production.

10. •Management
►Infected plant debris should be collected and
destroy, ploughed fields should be left open to
sun during summer.
►Seed treatment with hot water at 50°C for 30
minutes.
►Regular sprays of fungicides like 0.2% Dithane
M-45, Dithane Z-78, Duter, Difaroton.

11. Downy Mildew
►This disease has been reported from
all parts of country mainly in Uttar
Pradesh and Bihar.
►The infection is common in young
plants.

12. •Symptoms
►Purplish- brown spots containing downy growth of
pathogen on the lower side of the young leaves and the
region just opposite to these on the upper surface of the
leaves turn to yellow.

13. •Causal Organism
Kingdom : Fungi
Division : Eumycota
Class : Oomycetes
Order : Peronosporales
Family : Peronosporacea
Genus : Peronospora
Species : parasitica

14. Causal Org……
►Pathogen is obligate parasite
Hyphae are coenocytic, strictly intercellular with finger
shaped, branched houstoria.
►Conidiophores are unbranched for about two-third or
more of their length and possess dichotomous
branching (6-8 times) at their tips.
►The branches are long , slender and pointed and are
called “ sterigmata”.
►The conidia are colourless and broudly oval to elliptical.

15. Causal Org…….

16. •Disease Cycle

17. •Management
►Field sanitization and crop rotation.
►Infected plant debris should be collected and
burnt.
►Fungicidal sprays:- Dithane Z-28 (0.3%) ,
Dithane M-48 (0.1-0.3%), Diconil (0.1%), Ridomil
( 0.1%), Blitox-50 (0.2%) should be sprayed at
8-10 days interval.

18. .......
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