The document discusses Groundnut Bud Necrosis Virus (GBNV), a tospovirus that infects groundnut crops. GBNV is transmitted by thrips insects and causes symptoms including chlorotic spots, bud necrosis, and stunted plants with small seeds. It has a wide geographic distribution in Asia and Africa. Management strategies include controlling thrips vectors with insecticides, using resistant varieties, and cultural practices like proper planting dates and densities. The document also briefly discusses Groundnut Rosette Virus, which causes rosette disease and is transmitted by the aphid Aphis craccivora, along with its symptoms, transmission, and management.
HMCS Max Bernays Pre-Deployment Brief (May 2024).pptx
GROUNDNUT BUD NECROSIS VIRUS
1. COLLEGE OF AGRICULTURAL TECHNOLOGY
Affiliated to Tamil Nadu Agricultural University , coimbatore
Kullapuram, Via Vaigai Dam, Theni-625 562
GROUNDNUT BUD NECROSIS VIRUS
STUDENT COURSE TEACHER
PRIYADHARSHINI. P Dr. S. PARTHASARATHY
ID. No. 2016021035 Asst. Prof., (Plant Pathology)
2. • Bud Necrosis Disease (BND) is caused by two
serologically distinct viruses, Bud Necrosis Virus
(BNV) and Tomato Spotted Wilt Virus (TSWV).
• The virus is transmitted by thrips, Frankliniella
schultzei and Scirtothrips dorsalis hood.
• The virus is potential threat to groundnut because the
virus and vector have a wide host range.
SIGNIFICANCE
3. • Groundnut Bud Necrosis Virus (GBNV) was first
described in India in 1968 and later determined to
cause by infection of tospovirus.
• Tospovirus are among the most important crop plants.
• Until 1990, Tomato Spotted Wilt Virus (TSWV), the
namesake virus of the tospovirus genus, was
considered to be the only species of tospovirus.
SIGNIFICANCE
4. • However, in 1992 it was suggested based on serology
that bud necrosis of groundnut was caused by a
tospovirus different from TSWV and the virus was
named as Groundnut bud necrosis virus.
• Tospovirus species are often distinguished from each
other based on the amino acid sequence of the
nucleocapsid (N) gene.
SIGNIFICANCE
5. GLOBAL DISTRIBUTION
• BNV was first recorded in Brazil in 1941.
• Significant crop losses by this disease have been
reported from Australia, India, and the USA.
• Widespread throughout the country infecting many
crop.
• Asia : Bangladesh, china, India, Iran, Nepal, Pakistan,
Sri Lanka, Thailand and Vietnam.
8. • The typical symptom on groundnut is the appearance
of chlorotic rings, necrosis of terminal bud, severe
stunting, proliferation of auxiliary shoots with
deformed leaves.
• The infected plants produce small, discolored and
shriveled kernels.
• Young leaflets develop mild chlorotic mottle that
later develop into chlorotic and necrotic ring spots
and streaks.
SYMPTOMS
9. • The necrosis later extends to petioles, stems and
terminal buds.
• Infected plant show a stunted growth, deformed
leaves and a general chlorosis.
• Small and shriveled seeds are unfit to market to
reduce of the yield.
SYMPTOMS
10. Later the chlorotic spots and necrotic rings the plant die.
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11. Terminal buds of plants are affected when temperature
are relatively high. Leaflets produced on auxiliary shoot
show mosaic and general chlorosis.
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12. Early infection results in stunting of plants due to
multiplication of affected terminal buds.
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13. Any seeds produced by early-infected plants are small,
shriveled, and with spots.
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14. • Initial symptoms are concentric rings or chlorotic
spots on young leaflets.
• Subsequently terminal bud necrosis occurs especially
when day temperature exceed 30 degree Celsius.
• Plants infected at early stages are severely stunted.
• Occasionally, necrosis may spread to the petioles and
then to the stem leading to death of the plant.
SYMPTOMS
15. • Later the infected plant show bud necrosis on a few
branches and auxiliary shoot proliferations may be
restricted to the terminal portion.
• In early infection, pods are seldom produced.
• In late infections, pod size is reduced, shriveled, and
mottled with discolored testa.
• The virus is not transmitted by seeds; it is transmitted
by the thrips.
SYMPTOMS
16. PATHOGEN
• Regnum : Virus
• Group v : ssRNA(-)
• Class : Not assigned
• Order : Not assigned
• Family : Bunyaviridae
• Genus : Tospovirus
• Species : Groundnut bud necrosis virus
17. PATHOGEN CHARACTERS
• Size : 80-120mm
• Shape: Quasispherical
• Genetic material :
nucleic acid (-ssRNA)
Tripartite genome (L, M and S)
Large (L) (-8.9Kb) -Replace associated proteins.
Medium (M) -Movement and glycoproteins.
Small (-2.9) -Nonstructural and nucleocapsid.
proteins
18. • Symptom variant.
• Virulence variant.
• Difference in thrips specificity.
• Ability to break host resistance.
• Mechanically transmitted with difficulty.
• Exclusively transmitted by thrips.
PATHOGEN CHARACTERS
19. EPIDEMOLOGY
• Tospovirus are prevalent in warm climate in regions
with a high population of thrips.
• A survey by Gopal et al. (2011) found that GBNV
incidence was higher in rainy season crops than in
post – rainy season crops.
20. MODE OF SPREAD
• Primary spread – Thrips coming from other crops or
weeds.
• Secondary spread – Infected plants within the same
field.
• Spread of this virus in groundnut, is mostly
Monocyclic and disease incidence in this host
depends on infection by thrips that acquire the virus
from other crops or weed hosts.
21. HOSTS
• Tomato, Potato, Bean, Pea and other legumes.
• Primary sources of GBNV include a range of
solanaceous and fabaceous hosts which can sustain
viral infection and support thrips vector
multiplication.
22. TRANSMISSION
• Tospovirus are transmitted by thrips insects in a
circulative and propagative manner.
• A unique feature of the thrips – tospovirus
relationship is that only adults which acquired the
virus at the first larval stage are able to transmit the
virus.
• Larval and adult thrips both transmit GBNV in a
persistent manner.
23. • Circulative persistent manner of transmission.
• I and II instar larvae are effective in transmission.
• Adults acquiring the virus is Dead end of
epidemiology.
TRANSMISSION
25. MODE OF SURVIVAL
• The increased prevalence is largely because of the
successful survival of the thrips vector Scirtothrips
dorsalis, has also been implicated in the transmission
of at least three tospovirus.
• The success of this virus is due to the acquisition of a
gene in the M segment of the genome which encodes
the movement protein.
• The gene encoding this protein was likely acquired by
recombination from either a plant host or from
another host.
26. MANAGEMENT
• Application of dimethoate (Rogor) 30EC (400 ml/ha)
or oxydemeton methyl (Metasystox-R) 25EC (360
ml/ha) for controlling vectors may reduce the
incidence of disease.
• Roughing of diseased plants with high planting
density should be combined to limit the infestation.
• Use resistant / tolerant cultivars: ICGS 11, ICGS 44,
ICGV 87141, ICGV 87187, ICGV 87119, ICGV
87160.
• Control of vector (thrips).
27. • Adjust date of sowing to avoid the peak disease
incident.
• Sow groundnut at a high plant density and maintain a
good plant stand.
• Intercropping of groundnut with cereals, pearl millet
will restrict spread of the virus.
• Avoid groundnut cultivation adjacent to the crops that
susceptible to BNV, such as green gram or black
gram.
MANAGEMENT
28. GROUNDNUT ROSETTE VIRUS
COLLEGE OF AGRICULTURAL TECHNOLOGY
Affiliated to Tamil Nadu Agricultural University , coimbatore
Kullapuram, Via Vaigai Dam, Theni-625 562
STUDENT COURSE TEACHER
PRIYADHARSHINI. P Dr. S. PARTHASARATHY
ID. No. 2016021035 Asst. Prof., (Plant Pathology)
29. GROUNDNUT ROSETTE VIRUS
SIGNIFICANCE
• The groundnut originated in South America where it
has long been domesticated.
• It is an important subsistence crop in Sub – Saharan
Africa.
• Groundnut rosette virus was first described in Africa
in 1907 and causes serious damage to groundnut
crops on that continent.
• The virus can spread rapidly through a crop.
30. GLOBAL DISTRIBUTION
• Groundnut Rosette Disease (GRD), which is endemic
to Sub- Saharan Africa (SSA) and its off – shore
islands, is widespread.
• GRD is the most important disease in Uganda.
• GRD is first documented at the twentieth century in
Tanzania and South Africa and reported in all
groundnut growing regions of SSA and in
Madagascar.
32. SYMPTOMS
• The disease is severe in dry weather conditions.
• The affected plants remain stunted and show bushy
appearance as the nodes and internodes are shortened.
• Mosaic mottling becomes visible.
• Early infection cause small, sessile flowers which do
not open.
• The symptoms of the disease are caused by a Satellite
RNA co-infection, a subviral agent.
33. SYMPTOMS
There are three main type of symptoms:
• Chlorotic rosette is common in Sub-Saharan Africa.
Young leaflets become slightly mottled and older
leaflets become chlorotic with green veins.
• Mosaic rosette is prevalent in East and central Africa.
Young leaves have green and yellow mosaic
appearance and later symptom resemble chlorotic
rosette.
• Green rosette from West Africa, Northern Malwi,
Uganda and possibly Angola. Younger leaves show
mottling and flecking with older leaves. The plants
are severely stunted and resemble plants infected with
Groundnut clump virus.
34. • The disease is caused by a complex of three agents:
Groundnut rosette virus (GRV)
Satellite RNA
Ground rosette assistor virus.
35. Green rosette symptom Yellow/ Chlorotic
rosette symptom
http://www.researchgate.net
SYMPTOMS
36. Symptoms of groundnut rosette virus and assistor virus
http://alchetron.com http://www.researchgate.net
37. A groundnut field heavily affected by rosette virus
http://www.researchgate.net
38. TRANSMISSION
• Aphis craccivora (Koch), the known vector,
transmitted the virus by feeding on germinating
groundnut seeds.
• All larval forms and alatae and apterous adults might
transmit.
• Aphis craccivora , when it suck the sap of an infected
plant it receives groundnut rosette virus and satellite
RNA, packaged together within a coating of
groundnut rosette assistor virus.
40. PATHOGEN
• Group : Group IV (+)ssRNA
• Order : Not assigned
• Family : Tombusviridae
• Genus : Umbravirus
• Specie : Groundnut rosette virus
41. MANAGEMENT
• Rouge out the infected plants as soon as these appear in
the field.
• To check the aphid population spray oxydemeton methyl
(Metasystox-R) 25EC at the rate of 425 ml in 200 litres of
water per hectare.
• Cultural practices such as early sowing at optimal plant
densities are known to reduce the disease resistant.
• Rosette resistant groundnut varieties RMP 12, RMP 91,
RG 1.
42. • In 1982, ICRISAT established a Regional Groundnut
Improvement Program for Southern Africa based in
Malawi to develop agronomically and commercial
acceptable Groundnut varieties with resistant to
rosette.
• In 1990, ICRISAT- Lilongwe launched a program of
screening of global germplasm for resistant against
rosette.
MANAGEMENT
43. REFERENCE
• Saha, L. R., and Dhaliwal, G.S., 2009. Handbook of
Plant Protection. Kalyani publishers, New Delhi.
• Kenneth, M. Smith., 1972. A Textbook of Plant Virus
Diseases. Longman Group Limited, London.
• https://www.researchgate.net
• http:link.springler.com
