whitefly as vector,whitefly species, biotypes of whitefly, types of virus, virus-vector relationship,insect act as vector, major crop disease, transmission of virus by whitefly and management of whitefly.

2. Presented by
Bharat S Borude
M.Sc(Agri)Entomology
PG15-ENT1587
Seminar Incharge
Dr. D. B. Undirwade
Head
Department of Entomology
Dr. P.D.K.V. Akola
Chairman : Dr. S.K. Bhalkare
Assistant professor
Department of Entomology
Dr.PDKV Akola

3. Whitefly
 The whitefly was first reported in Greece
125 years ago.
 It became a major pest on cotton in India only after 1984.
 Whitefly feeds on more than 500 plant species and transmits a
range of viral diseases in plants.
Taxonomic position
Kingdom : Animalia
Phylum : Arthropoda
Class : Insecta
Order : Hemiptera
Family : Aleyrodidae
Genus : Bemisia
Species : tabaci
 1550 species recorded
Source : Wikipedia

4.  Insect vectors of plant viruses are found in 7 orders of the
class Insecta.
 The majority of vectors are found in the two orders of
insects with pierce-sucking mouthparts (number of species
in parenthesis): Hemiptera (300) and Thysanoptera (6).
 Other vector species are found in five orders of chewing
insects: Coleoptera (30), Orthoptera (10), Lepidoptera (4),
Diptera (2) and Dermaptera (1).
 Over 1300 whitefly species in over 120 genera have been
described with only the Bemisia and Trialeurodes genera
being virus vectors.
 There are 3 important species. About 114 viruses are
transmitted by these 3 spp.
 Bemisia tabaci -108 viruses
 Trialeurodes vaporariorum -3 viruses
 Trialeurodes abutilonea -3 viruses
(Mound and Halsey, 1978)and )(Fereres and Raccah, 2015)

5. 1) Greenhouse whitefly -
Trialeurodes vaporariorum
2) Sweet potato whitefly -
Bemisia tabaci
3) Bandedwing whitefly -
Trialeurodes abutilonea
Common whitefly species
Source : Wikipedia

6. Whitefly species identification
species egg nymphs adult
T. vaporariorum
GHWF
SPWF
B. tabaci
Source : Google Image (Wikipedia)

7. Biotypes of B. tabaci. host associations, and virus
transmission
UYV, = lettuce infectious yellows virus; AGMV, Asystasia golden mosaic virus; TYLCV·Ye, tomato
yellowleaf curl virus, Yemen; JMV, Jatropha mosaic virus; ACMV, African cassava mosaic virus.
Brown et.al.1995.

8. LIFE CYCLE OF WHITEFLY
yellowish white
Source : Wikipedia

9.  Under surface of the leaves
 Both nymphs and adults
 Needle like mouthparts - vascular tissue / phloem
 Suck the plant sap.
 Excreting honey dew on which sooty mould grows.
NATURE OF DAMAGE
Whitefly adults Whitefly nymphs

10. •During 2015-16 an epidemic of whitefly incidence
was noticed during August in the cotton growing
areas of Haryana, Punjab and Rajasthan.
•In 2015-16, Punjab had 4.50 lakh hectares under
cotton crop. The drop in acreage is a massive
43.11% in just one year with wary farmers shifting
to other crops.
•The crop loss due to this is estimated at 40-50 per
cent of the total or 1.5 to two million bales (a bale
is 170 kg).
(http://timesofindia.indiatimes.com/city/chandigarh/WhiteflyfearCottonacreagedrops-
to61yearlow/articleshowprint/53135445.cms?null)
ECONOMIC LOSSES DUE TO
WHITEFLIES

11. (The Hindu,October 18,2015)

12. Vector
 Definition: A vector is any agent (microorganism) that
carries and transmits an infectious pathogen into another
living organism.
FACTS of Transmission of Plant Viruses
 Plant viruses do not penetrate the intact plant cuticle.
 Not disseminated as such by wind or water, and even when they
are carried in plant sap or debris
 Generally do not cause infections unless they come in contact
with the contents of wounded living cell
1. Mechanical contact
2. Grafting
3. Vegetative propagation
4. Botanical (sexual) seed
5. Pollen
Source: (Fereres and Raccah, 2015)

13. The Importance of Insect Vectors
Most plant viruses depend on vectors for their survival for two
principal reasons:
 An impermeable cuticle coats the plant epidermis preventing
entry of virus particles (animal viruses enter readily through
natural openings). Most vectors are insects. Several plant viruses
may spread by contact or vegetative reproduction. Many insects
such as hemipterans are well adapted to their role as vectors by
their capacity to pierce the epidermis and delicately deposit the
virus in the cytoplasm without risking the integrity of the plant
cell. Recent findings propose that viruses have adapted to their
vectors modifying their behaviour to maximise their own spread.
 Plants are rooted and lack independent mobility. Therefore, many
viruses depend on insects for transport among hosts (unlike
animals that, by their own mobility, transport the virus to new
niches).
Sorce: (Fereres and Raccah, 2015)

14. Types of viruses based upon the action of vector
 Stylet-borne viruses(non-persistent)
 The association occurs within the feeding apparatus of the insect, where
the virus can be rapidly adsorbed and then released into a different plant
cell. The feeding insect looses the virus rapidly when feeding on a non-
infected plant.
 Cucumoviruses, carlaviruses and potyviruses
 Circulative viruses(semi-persistent)
 Circulate through the tissues of the vectors. Not transmitted immediately
after the acquisition but the vectors have to wait several hours
 Maize chlorotic dwarf virus,rice tungro virus,potato leaf-roll virus.
 Propagative viruses(persistent)
 Viruses start multiplying within their vectors and establish a biological
relationship viruses possess an incubation period. Almost all leafhopper
transmitted viruses are propagative. Vector remain viruliferous throughout
their life.
 Wheat streak mosaic virus. Source: (Whitfield and Rotenberg (2015)

15. Virus-Vector Relationship
 Non-circulative viruses are retained in the insect stylet (A) or foregut (B).
 Non-propagative circulative (yellow circles) viruses are generally phloem
limited and penetrate the insect body via the midgut or hindgut.
 Circulative viruses use a hemolymph route to reach the salivary glands.
 In contrast, circulative propagative viruses (red ovals) enter the insect at the
anterior region of the midgut and/or filter chamber region.
 Propagative viruses may use a
hemolymph route and others such as
the Rhabdoviruses also use a
neurotropic route to reach the
salivary glands.
 Propagative viruses replicate in the
midgut cells and other insect tissues.
Source: (Whitfield and Rotenberg (2015)

16.  The salivary glands are the final destination for circulative transmission, and
viruses reach the salivary glands via the hemolymph or other routes such as the
nervous tissue (neurotropic route) or through connective tissues.
 Reoviruses use tubules to move cell to cell in the midgut and another uses the
tubular structure to traverse the basal lamina (C).
 Insets: Magnification of an insect stylet showing the proposed site of virion
attachment at the tip of the stylet in the common duct region (A).
 Numbers designate the different strategies
for virion binding and retention in the
stylet: capsid strategy, direct binding of
capsid protein to the stylet (1), helper
component strategies for caulimoviruses,
two virus proteins serve as a “bridge”
between the virion and the stylet (2) and
potyviruses, one virus protein (HC-Pro)
binds to the aphid stylet and to the virus (3).
Source: (Whitfield and Rotenberg (2015)

17.  Inset B: Magnification of the foregut retention site and proposed capsid binding strategy
used by Criniviruses. The minor capsid protein (CPm) is the viral attachment protein.
 Inset C: The steps in the reovirus infection cycle and spread to adjacent cells modeled on
Rice dwarf virus. Rice dwarf virus enters cells using the endocytic pathway and after
virion release from the vesicle the replication cycle begins.
 Progeny virions move cell-to-cell via tubule structures composed of virus nonstructural
protein. This enables virions to move directly from one cell to another without an
extracellular phase.
(Whitfield and
Rotenberg (2015)

19. Insects act as vector are………
 Aphid
 Whitefly
 Hopper
 Thrips
 Mites (non insect)
 Others (psylla, leaf miner )

20. • Leaf curl of chilli
• Bud necrossis of
groundnut
• Wheat streak
mosaic
• Sterility mosaic of
tur
• Rice tungro virus
(Nephotatix
viruscens)
• Maize streak
virus
• Bunchy top of
banana
(Apentelus sp)
• Papaya mosaic
• Potato leaf roll
virus
• Citrus tristeza
virus
Source: Applied Entomology (book) and wikipedia

21. Citrus psylla
(Diphorina
citri)
Citrus
greening
(Mycoplasma)
Leaf miner
(Phyllocnistis
citrella)
Citrus canker
(Bacteria)
Source: Applied Entomology (book) and wikipedia

22. Whitefly transmitting viruses
Geminivirus
(Begamovirus)
Crinivirus
Closterovirus
(www.planthealthaustralia.com.au/go/p
hau/biosecurity/general-biosecurity-
information).

23. Whitefly
Tomato leaf curl
virus
Cotton leaf curl
virus
Bhendi yellow
vein mosaic virus
A) Geminivirus (Begamovirus)
Source: Plant health Australia PHA & NGIA | Contingency Plan –
Whitefly transmitted viruses oct. 2010

24. Mung bean yellow
mosaic virus
Soybean crinkle
leaf virus
Cabbage leaf curl
virus
A) Geminivirus (Begamovirus)
Source: Plant health Australia PHA & NGIA | Contingency
Plan – Whitefly transmitted viruses oct. 2010

25. Cucumber
yellows virus
Lettuce
chlorosis
virus
Tomato
chlorosis
virus
B)Crinivirus
Source: Plant health Australia PHA & NGIA | Contingency
Plan – Whitefly transmitted viruses oct. 2010

26. Grapevine corky
bark-associated
virus
Little cherry
virus 1
Sugarcane mild
mosaic virus
C)Closterovirus
Source: Plant health Australia PHA & NGIA | Contingency
Plan – Whitefly transmitted viruses oct. 2010

27. Leaf Curl of Cotton
 Leaves of infected cotton curl upward and bear leaf-like
enations on the underside along with vein thickening.
 Leaves curl upwards and the plant vigour reduces.
Leaves become shiny with honeydew or darkened
by sooty mould growing on honeydew.
 Lint contamination with honeydew and associated
fungi occur during heavy infestations
after boll opening.
Source: www.cicr.in

28. Yellow Vein Mosaic of okra
Yellowing of the entire network of veins in the leaf
blade is the characteristic symptom.
In severe infections the younger leaves turn yellow,
become reduced in size and the plant is highly stunted.
Infection may start at any
stage of plant growth.
Source: Wikipedia

29.  The most common indicator of
the disease is the yellowing and
upward curling of the leaves,
which may also appear crumply.
 Plant growth soon becomes
stunted and may even take on a
bush-like growth habit.
 Flowers usually will not develop
and those that do simply drop
off. In addition, fruit production
will be significantly reduced.
 TYLCV is transmitted exclusively by the
whitefly Bemisia tabaci.
Soruce: Castillo et.al.2011

30. Management of whitefly
 Judicious application of N fertilizers
 Grow inter crops and trap crops like BG, GG, soybean
cluster bean cowpea and groundnut with cotton and grow
castor and tomato as trap crops as border crops
 Destroy the infested plants and weeds surrounding the field
 Erect the yellow sticky traps 10-12/ha or keeping yellow
empty tins smeared with grease as trap. Wipe out trapped
whiteflies every day and apply grease again
 Destroy the different stages of the insect by collecting the
infested leaves and affected parts of the plant by polythene
covers to avoid contact with other plants
 Natural enemies like mirid bug and spiders

31.  Seed treatment -Carbosulfan - 40 g/kg, Imidacloprid 70 WS - 5 g/kg and
Thiamethoxam 70 WS - 4 g/kg
 Soil application- Carbofuran 3G 12 – 14 kg/ac or Phorate 10G 4 – 5 kg/ac
nearer to the base of seedlings when the soil is moist
 Stem application-Monocrotophos or methyl demeton 1:4 with water
Imidacloprid 200 SL 1: 20 with water 20 – 25, 30 – 35 and
40 – 45 DAS
 Foliar spray:
Azadirachtin 0.15% W/W 2.5l-5.0l
Azadirachtin 5% W/W 750 ml/ha
Difenthiauron 50SC 300gm/ha
Buprofezin 25% SC 1000ml/ha
Carbaryl 85% W.P. 1411 ml/ha
Dimethoate 30% EC 990 ml/ha
Monocrotophos 36% SL 375 ml/ha
Oxydemeton – methyl 25% EC 1000 ml
Phosphamidon 40% SL 625-750 ml/ha
Spiromesifen 22.9% SC 600ml/ha
Thiacloprid 21.7% SC 500-600 ml/ha
Imidacloprid 17.8% SL 100-125
Source: Applied Entomology

32. NBRI developed whitefly resistant
transgenic Cotton
 The team of scientists isolated an anti-whitefly gene
named TMA12 from an edible fern Tectaria sp.. This fern
has been maintained in NBRI garden for the past 50 years.
 One of the proteins was isolated from an edible fern
Tectaria sp, which is lethal to Whitefly and interferes in
its reproductive process.
 This fern’s anti - whitefly protein was
introduced in cotton to translate the
potential of protein into a technology.
 The selected transgenic cotton lines
shows remarkable control of whitefly
population through several generation. Pradhymna Singh with whitefly
resistant transgenic cotton plants.
Source: www.nbri.res.in

33. CONCLUSION
Whitefly is a polyphagous, migratory and highly
resistant pest. Synthetic organic pesticides caused
resurgence of the pest leading to the death of the farmers
recently occurred in Punjab and Haryana in India.
Considering the economic importance of the pest,
scientists and farmers have been taking profound practices
to manage the whitefly including cultural, host plant
resistance, biological and least importance to the older
molecules which already developed resistance to the
whitefly and including the newer molecules in a need based
application. NBRI developed white fly resistant transgenic
cotton. This gives farmers the hope that an overdose of
fertilisers and pesticides would save the plant. But there is a
need to develop transgenic crops which resist the sucking
pest complex of different crops.

34. Reference
 http://timesofindia.indiatimes.com/city/chandigarh/WhiteflyfearCottonacreage
dropsto61yearlow/articleshowprint/53135445.cms?null.
 http://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-leaves-curling.htm
 Kranthi K. R.2015. Whitefly-the black story cotton statistic and news cotton
association of India, no.15 www.cici.org.in.
 Mound LA, Hasley SH (1978) Whitefly of the World, a systemic catalogue of the
Aleyrodidae(Homoptera) with host plant and natural enemy data.
British Museum (Natural History), London and John Wiley and Sons,
Chichester UK.
 Ng, J.C., Falk, B.W., 2006. Virus–vector interactions mediating nonpersistent and
semipersistent transmission of plant viruses. Annu. Rev. Phytopathol. 44,
183–212.
 Raccah B. and Fereres A. 2009.plant virus transmission by insects Encyclopedia of life
science (ELS), Jhon Willey and sons, ltd. chichester .
 Whitfield, A.E., Rotenberg, D., 2015. Disruption of insect transmission of plant
viruses. Curr. Opin. Insect Sci.
 www.nbri.res.in
 www.wikipedia.com