History, symptoms,systematic position, mode of spread, Favourable condition,management

1. COTTON LEAF CURL VIRUS
COURSE TEACHER
Dr. PARTHASARATHY S
Asst. Professor (Plant Pathology)
STUDENT
Miss. SRIMATHI P
ID. NO. 2015021124
COLLEGE OF AGRICULTURAL TECHNOLOGY
(Affiliated to Tamil Nadu Agricultural University, Coimbatore-3)
Kullapuram (Po),ViaVaigai Dam, Theni-625 562

2. Cotton leaf curl virus
Common Name : leaf curl disease of cotton
International Common Names : cotton leaf crinkle;
cotton leaf curl disease; leaf crinkle of cotton.
Virus
In Pakistan & North India - Cotton leaf curl virus.
In India (South India) - Tobacco streak virus.

3. History & its significance
 First time cotton leaf curl disease was reported in
Nigeria during 1912 (Farquarson, 1912).
 Later on reported from Tanzania and Sudan in 1926
and 1934 respectively (Bailey, 1934).
 In Pakistan cotton leaf curl virus was reported for the
first time in 1967 near Multan (Hussain, 1975).

4.  CLCuVD is passed on by its vector whitefly (Bemisia
tabaci) and belongs to the genus Begomovirus
family Geminiviridae (Hameed et al., 1994).
 Cotton Leaf Curl Virus Disease (CLCuD) is the most
destructive disease causing huge losses to cotton
production. (Khan and Ahmad, 2005).

5.  There were intermittent reports of increase in disease
spread mostly around Multan, Khanewal and Vehari
which reached an epidemic proportion in 1993 with
8.9 lakh hectares that comprised about one-third of
Pakistan’s cotton area under the severe grip of the
virus.
 The production was 128 lakh bales in 1991-92 but
declined to 79 lakh bales during the epidemic years
in 1994-95 indicating 30-40% losses due to the
disease. This epidemic was caused by the ‘Multan
species CLCuMuV’.

6.  LRA 5166 as a resistant donor and cultivate the
resistant varieties especially in hot-spot districts.
 There was a second outbreak in the Burewala area of
Punjab province during the 2001-02 season and
reduced the production to 100 lakh bales in the years
2002 and 2003. A new ‘Burewala CLCuBuV
species’ had infected all the varieties that were
resistant to the ‘Multan CLCuMuV species’.

7.  India experienced the leaf curl virus outbreaks in 1993
& 1996 just concurrent to the occurrence of
epidemics in Pakistan during 1992 and 1995.
 The leaf curl virus damage in India during the years
1998 to 2006 declined due to the cultivation of
resistant varieties and intensive measures to control the
whitefly and weeds.
 The complete replacement of varieties with new Bt
cotton hybrids after 2007 changed the scenario.

8.  By 2011, the area under Bt cotton hybrids reached more
than 90% in Punjab and Haryana but was less than 70%
in Rajasthan.
 It is probable that the slow rate of adoption of the new
Bt -hybrids in Rajasthan resulted in low to moderate
levels of disease incidence in the state.

9. SYMPTOMS
Cotton Leaf Curl Disease (CLCuD) infected plants
may show a range of symptoms depending on the
severity of disease,
 Typical symptoms include thickening and yellowing of
small veins on the lower surface of young leaves.
 Under severe attack of the disease, leaves curl downward
or upward with stunted plant growth due to reduction
of inter-nodal distance.

10.  The severity of disease also produces a cup shape
outgrowth on the lower side of the curled leaves that is
known as Enation.
 The appearance of the disease at seedling stage seriously
retards the flowering, boll formation, maturation, seed
cotton yield and fiber quality.
SYMPTOMS

11. ©Padil
Infected plant

12. ©Intechopen
(a) Healthy Leaf (b) Infected Leaf

13. ©Australian journal of crop science
Leaf enation

14. SYSTEMATIC POSITION OF LEAF CURL VIRUS
Domain: Virus
Unknown: "DNA viruses"
Unknown: “ssDNA viruses"
Family: Geminiviridae
Genus: Begomovirus
Species: Cotton leaf curl virus

15. SYSTEMATIC POSITION OF TSV
Domain: Virus
Unknown: "RNA viruses"
Unknown: "Positive sense ssRNA viruses"
Family: Bromoviridae
Genus: Ilarvirus
Species: Tobacco streak virus

16. MODE OF SPREAD
Through vector - Bemisia tabaci (White fly)
 Whitefly (B. tabaci) is a member of order Hemiptera
and family Aleyrodidae. Virus is transmitted in a
persistent and circulative fashion.
 The virus is not transmitted transovarially by the
vector.
 B. tabaci feeds on phloem sap by inserting its stylets
into plant tissue and locating the vascular tissue.

17.  Whiteflies require an acquisition threshold period
ranging from 15 min to 4 h and an inoculation
threshold period of 5 min to 1 h to successfully
transmit the virus.
 Upto 8 h latent period is also required between the
acquisition and inoculation periods for successful
transmission of the virus to new plants.

18. ©Cotton association of India
Whitefly - Adult

19. FAVOURABLE CONDITION
 Cotton leaf curl virus disease (CLCuD) is affected by
climatic conditions like rainfall, wind and Temperature.
 Disease infestation increased in the range of maximum
and minimum temperatures of 33-45°C and 25-30°C
respectively.

20.  Maximum disease incidence % was recorded at 6
week old seedlings and it gradually decreased with
increase in age of the plant.
 Rainfall prior to seedling may result in development
of an increased population of vector due to abundance
in food source.

21. MANAGEMENT
 Adjust sowing time (mid April to mid May results in
decrease of disease incidence).
 Increased plant spacing in the case of early sowing
and decreased plant spacing under late sown conditions
is effective in management of CLCuD.
 Destroy infected plants, especially after harvest.
 Crop rotation with crops that are not host plants for
whiteflies.

22.  Destruction of off- season weeds and clean cultivation
during the season to minimise sources of virus inoculum.
 Avoid cultivation of malvaceous crops such as okra
(bhendi) or tomato especially in disease prone areas.
 The applications of organic oils (canola, sunflower and
cotton seed) were done at 25% concentration (25% oil
and 75% vinegar) on young cotton plants in order to
create hurdle against insect vector infestation.

23.  Insecticides (Imidacloprid (Imidacloprid 25% WP),
Megamos (Acetamparid 20% SC and Bifenthrin
(Bifenthrin 10% EC)) were sprayed at their
standard doses in the field for maximum mortality of
whitefly with 7 days interval.
 Grow resistant varieties like XL1, L1530, X1730A,
X 1030, B 6 L, RS - 875, RS - 810, RS - 2013, F 1861,
L H- 2076, H-1117, H-1226 and hybrids LHH-144,
CSHH198, CSHH238 and CSHH243.

24. TOBACCO STREAK VIRUS
 Cotton necrosis disease caused by tobacco streak virus
(TSV) is an emerging threat in India (Rageshwari et al.,
2016).
 Tobacco streak virus (TSV) was first identified in
tobacco in Brazil (Johnson 1936; Costa 1945).

25.  In Tamil Nadu, Nakkeeran (AICRP report 2010) first
reported the association of TSV in cotton.
DISTRIBUTION
Tamil Nadu, Telangana, Andhra Pradesh and Maharashtra.

26. SYMPTOMS
 Initial symptom includes, (a) chlorotic lesions, which
may later turn into necrotic, purplish brown spots,
surrounded by yellow halos.
 The spots may be (b,c,d) chlorotic or necrotic, small or
large, (e) purplish or purplish brown or brownish black,
irregular or (f,g) ring-like, confined at the interlobular
region /apex or distributed all over the lamina.
 In cases of severe infection, (h) drying of squares,
stems and stunting of plants were also observed.

27. © www.researchgate.net/publication/320507097

28. MODE OF SPREAD
Through vector – Thrips (Thrips tabaci)
 TSV is transmitted by infected pollen from alternate
hosts and the only know mechanism of insect
transmission is ingress of the virus from the pollen
through wounds made by the action of thrips feeding
on the leaf.
 The thrips do not transmit the virus directly through
feeding, as with most other insect-vectored viruses.

29. FAVOURABLE CONDITION
Minimum temperature (22.81°C), relative humidity
(81.42%), and leaf wetness (23.94 h).
MANAGEMENT
 Remove plant debris after harvest or any plant material
that may serve as a source of inoculum.
 Keeping fields free of weeds is a good control strategy.
 Spinosad is generally more effective against thrips.
 One common form of management for viruses is to plant
a desirable host for thrips around the cropping system.
The thrips will insert their stylet and “clean” off any
virus on their stylet before moving to the target crop.

30. REFERENCES
https://www.icac.org/tis/regional_networks/asian_ne
twork/meeting_5/documents/papers/papmongad.pdf
https://www.plantwise.org/KnowledgeBank/Datashe
et.aspx?dsid=16813
https://www.ncbi.nlm.nih.gov/pubmed/11137169
https://www.sciencedirect.com/science/article/pii/S0
168170200001957
https://www.cabi.org/isc/datasheet/16813
 https://agrihunt.com