This video cover major disease cause by the virus and viroides

1. – VIRUS & VIROID DISEASE
PRESENTED BY
Mohit kumar meena
Agriclaas7073@gmail.com
DEPARTMENT OF BOTANY

2. DISEASE- Disease is any malfunctioning of host
cells and tissue that result from continuous
irritation bya pathogenic agent or environmental
factor that leads to development of symptoms.
• In 1892
D.IVANOVASKI try to
filter the sap of
Infected tobacco
plant
• The filters was
capable to producing

4. VIRUS DISEASE -

5. • A simple virus particle designated as virion consist
of nucleic acid enclosed with protein coat.
• Size- ranging between 20-350nm
• Largest virus- orthopoxvirus 240×300nm
• Smallest virus- Enterovirus less than 30nm
• Nucleic acid- contain one type of DNA or RNA
Deoxyvirus- contain only DNA
Ribovirus- contain only RNARNA
• Mostly plant virus contain SsRna
• Protein coat- nucleic acid of Virus protected by
protein coat known as capsid (Monomer-
Virus

6. PATHOGEN: TOBACCO MOSAIC VIRUS
HOSTS: TOBACCO, TOMATO, AND OTHER SOLANACEOUS
PLANTS
INTRODUCTION - TMV WAS THE FIRST VIRUS TO BE
DISCOVERED OVER A CENTURY AGO AND WAS THE FIRST
VIRUS EVER PURIFIED.
• SHAPE – ROD LIKE
• Genome-TMV genome consists of a 6.3-6.5 kb
single-stranded (ss) RNA.
• TMV is a thermostable virus. On a dried leaf, it can
withstand up to 120 degrees Fahrenheit (50 °C) for
Tobacco mosaicdisease

7. SYMPTOMS
• Moasic
• Necrosis
• Mottling
• Stunting
• leaf curling
• yellowing of plant
tissues.

9. Disease name: Bhendi yellow vein mosaic
Pathogen name: Bhendi yellow vein mosaic virus
Host: Abelmoschus esculentus (L.) Moench
(bhendi, okra)
• first reported in okra plants in 1924 in India
and Sri Lanka.
• The whitefly Bemisia tabaci (Genn.) sibling
species group is the insect vector.
• Warm humid weather favours the infection
Bhindi yellow vein mosaic disease

10. • The symptoms include alternate green and yellow
patches, vein clearing, and vein chlorosis of
leaves.
• Fruits are dwarfed, malformed, and yellow
green.
• Infected plants stunted
• Thickinng of vein and ventricles.
• Less flowering.
• Yellowing of leaves and decrease in size.
Symptoms
:

12. Causal agent- yvmv
Very small in size
Shape-spherical
single-stranded DNA,which is associated with a
beta satellite
BYVMV belongs to the
genus- Begomovirus
family Geminiviridae

13. DISEASE CYCLE-
• Virus penetrates several weed , Ageratum spp.,
Croton sparsiflora. When Crop is absent.
• YVMV is not sap transmissible.
• It transmitted by the whitefly, Bemisia tabahci.
• The virus undergo an incubation period of seven
hour in vector.
• Then the vectore inoculate them on crop plant.

14. Ageratu
m
Croton
sparsiflora.
Whitefly

15. DISEASE MANAGEMENT
• Destroy weed host{(croton sparsiflora Ageratum) And
wild host (Hibiscus tetraphyllous)
• Diseased bhindi plant solid be sorted out, collected and
burnted.
• Spray suitable insciticides- # Follidol(0.3%)
# Soil application of methyl phosphorodithionate
(Furatox-IOG)
# Foliar spray of methyl rehmaton(metasystox25EC) at
interval of 15 days for four time.
Resistant variety- Pusa swani

17. PAPAYA LEAF CURL DISEASE-
Host: Carica papaya L. (papaya)
Disease name: Papaya leaf curl
Pathogen name: Papaya leaf curl virus (PLCV)
INTRODUCTION- Papaya leaf curl was first reported in Tamil
Nadu in 1939. Thomas and Krishnaswamy.
Disease occur Commonly in uttarpradesh, Bihar,
Andhra pradesh, Karnataka, kerla and other where
papaya is grown.

18. Symptoms
• Curling, crinkling and distortion of leaves,
reduction of leaf lamina, rolling of leaf margins
inward and downward, thickening of veins.
• Leaves become leathery, brittle and distorted.
• Plants stunted.Affected plants does not produce
flowers and fruits.
• Petioles become zig –zag manner.
• Plant can be diseased at any stage of life cycle.
• Plant become completely sterile.

20. Causal agent-TLCV tobacco leaf curl
virus(tobaccoVirus,Nicotianavirus10)
• The virus cannot be transferred mechanical means as in
the case of mosaic disease. The virus readily transmitted
through grafting and white fly (Bemisia tabaci).
• They show a mortality of 70 –80 per cent if forced to feed
continuously on papaya for more than 24 hrs.
• is assumed that the virus is acquired from alternate hosts
such as tobacco, Zinnia and various weeds
• Host Range The virus infects all the cultivars of papaya. It
can also infect tomato, tobacco, Sunnhemp, chilli, Pitunia,
Datura stramonium and Zinnia elegans. The virus also
perpetuates on a number of hosts.

21. Disease management
• There is no chemical treatment
for viral infections.
• Do not grow alternative hosts in
proximity of papayas.
• Uproot infected plants and
destroy them.
• Soil application at the time of
sowing and 4-5 foliar sprays of
dimethoate or metasystox at an
interval of 10 days can effectively
control whitefly populations
• Crop rotation.

24. DISEASE: Potato spindle tuber
PATHOGEN: Potato spindle tuber viroid
HOSTS: potato, tomato, ornamentals (Solanaceae)
• spindle tuber disease of potatoes was the first to
be recognized.
• PSTVd has been found infecting S. tuberosum
in some countries or states in Africa, Asia,
Eastern Europe, North America, Central America
South America and the Middle East.

25. SYMPTOMS AND
SIGNS-
• growth of infected plants may be severely reduced
• the vines of infected plants may be smaller.
• produce smaller leaves than their healthy
counterparts.
• Infected tubers may be small, elongate,misshapen,
and cracked.
• Their eyes may be more pronounced than normal.
• changes in the foliage, smaller leaves and spindle
like elongation.
• Leaves become yellow or purple and often become

27. PATHOGEN- Pstvd (potato spindil tuber viroid)
Group:Viroids
Family:Pospiviroidae
Genus:Pospiviroid
Species:Potato spindle tuber viroid,potato gothic virus,
tomato bunchy top virus
contain single standard RNA(ssRNA) Consisting of 359
nucleotidess
◆PSTVd moves long distances in the phloem.
◆PSTVd replication occurs in the nuclei of infected cells and
is catalyzed by RNA polymerase II,
◆a host-encoded DNA-dependent polymerase normally
involved in mRNA synthesis

28. Transmission-
●Vegetative propagation.
●Mechanical
transmission.
●Infected seed and
pollen.

30. DISEASE
MANAGEMENT
There are no chemical or biological controls
available to control PSTVd within infected plants.
Disease management can be divided into two
parts: prevention of infection and viroid
eradication.
Prevention-
Erediction-destruction of PSTVd-infected plants
and thorough cleaning of equipment and
greenhouses.
• Infected plant should be destroyed.