White flies are a major pest in greenhouse fruit crops. The warm, humid conditions in greenhouses allow whitefly populations to grow rapidly. Several whitefly species can infest fruit crops, with the greenhouse whitefly (Trialeurodes vaporariorum) and sweet potato whitefly (Bemisia tabaci) being most common. Integrated pest management for whiteflies in greenhouses includes prevention through exclusion barriers and sanitation, monitoring with yellow sticky cards, and control using biological controls like parasitoids and predators, entomopathogenic fungi and nematodes, and selective use of biopesticides or chemical pesticides.

1. WHITE FLY CONTROL IN FRUIT CROPS
UNDER PROTECTED STRUCTURE
FSC 511 PROTECTED CULTIVATION OF FRUIT CROPS
PRESENTED BY: ABEER ALI
ROLLNUMBER: 60071
MSC FIRST YEAR

2. INTRODUCTION
• Fruit crops such as melons, grapes, peaches, bananas, papaya,
strawberries, mangoes, and dwarf type fruits were grown in
protected structure.
• The warm, humid conditions and abundant food in a greenhouse
provide an excellent, stable environment for pest development.
• Often, the natural enemies that serve to keep pests under control
outside are not present in the greenhouse.
• For these reasons, pest situations often develop in this indoor
environment more rapidly and with greater severity than outdoors.
• The mere presence of whiteflies in a shade house/greenhouse will
reduce fruit quality and subsequent economic loss
• Crops grown in glasshouses or under similar protected
environments are often high value with extremely low infestation
thresholds, sometimes referred to as the “aesthetic threshold”
(Oetting and Buntin 1996)

3. WHITEFLIES - A MAJOR GREENHOUSE PEST
TAXONOMY
Kingdom Metazoa
Phylum Arthropoda
Class Insecta
Order Hemiptera
Family Aleyrodidae
Genus Bemisia
Species Bemisia tabaci
Whiteflies are a severe crop protection issue in warm or tropical areas,
and especially in greenhouses.
• They are small insects, with a wingspan of less than 3 mm and a body
length of 1 mm to 2 mm.
• Direct damages and symptoms include weak plants and yellow
mottled leaves, which are a direct result of their feeding.
• the indirect damage caused by whitefly – transmission of plant
viruses – can result in significant economic losses
• Whiteflies do not have a dormant stage that can withstand freezing temperatures.
• In climates that have winter freezes, such as Kentucky, whiteflies are year-round pests only in greenhouses.
(White, J. 2014)

4. IDENTIFICATION OF DIFFERENT
WHITEFLY SPECIES
• 1556 species of whiteflies recorded in the world (Sani etal., 2020)
Prominent pest species include:
 Aleurocanthus woglumi - citrus blackfly
 Aleyrodes proletella - cabbage whitefly
 Bemisia tabaci - silverleaf whitefly (0.8-1.2 millimetre ) or sweet
potato white fly
 Trialeurodes vaporariorum - greenhouse whitefly (0.9- 1.1
millimetre)
 Banded winged whitefly - Trialeurodes abutiloneus
The most common whiteflies on shade house/greenhouse crops are
• the shade house/greenhouse whitefly (Trialeurodes vaporariorum)
• Sweet potato whitefly (Bemisia tabaci)
• the silver leaf whitefly (Bemisia argentifolii).
White, J. (2014)

5. WHITE FLY IN FRUIT CROPS
• citrus fruits, fig, olive. pomegranate, plum, strawberry,
black berry, papaya are commonly affected by white
flies
• The greenhouse whitefly, Trialeurodes vaporariorum
(Westwood), is an important pest of horticultural crops
in greenhouses crops such as strawberry, raspberry,
cucumber, tomato, lettuce, citrus, bean and cotton (J.L.
Bi et al 2002)
• It was reported that papaya (Carica papaya L.) is a host
of the relatively host specific whitefly, Trialeurodes
variabilis, (Hemiptera: Aleyrodidae) (Lourencao et al.,
2007),
Adults (A) and nymphs (B) of Trialeurodes variabilis, infested petiole (C) and leaf
(D) of papaya associated with sooty mold (MARTINS et al., 2016)

6. Under ideal conditions, the full life cycle
of a whitefly takes around three weeks,
allowing populations to grow quickly.
Barbedo, 2014

7. THE GREENHOUSE ENVIRONMENT AND THE OCCURRENCE OF PESTS
The population of whitefly was gradually increased with environmental
temperature and humidity up to certain age of the cultivated crops then
declined with increasing age of the crops. (Latif étal., 2013)
there is a trade off between exclusion and ventilation as finer netting
means less air exchange with the outside and consequent rise of
temperature during the heat of the day (Harmanto and Tantau 2006;
Teitel 2006).
Hence forced air ventilation is preferred for air exchange

9. INTEGRATED PEST MANAGEMENT
PREVENTION:
A. Exclusion: by Use of physical barriers such as:
1. Use of insect-proof nets: Screen mesh of holes less than 200 micrometres is
required for complete exclusion. Insect-proof screens 10 x 20 micron and 10 x
22 micron give adequate exclusion of whiteflies Trialeurodes vaporariorum
and Bemisia tabaci without impeding natural enemies (Diglyphus isea and
Eretmocerus erimicus) movement. Greenhouse whitefly (T. vaporariorum) 58
mesh size (Rathe etal., 2018).
2. Provision of double door : partially solve the problem of wind-carried insects.
3. Use of reflective or metalized mulches: Metalized mulch was effective in
reducing silverleaf whitefly entrance by 90 per cent.
4. Ultra-violet radiation absorbing sheets : The UV part of the solar spectrum
plays an important role in the ecological behaviour of insects, including
orientation, navigation, feeding and interaction between the sexes.

10. INTEGRATED PEST MANAGEMENT
B) Sanitation
• removal of both infested materials and potential sources of infestation,
• followed by disinfection of surfaces and includes various approaches like, clean planting material, ventilation, clean or sterile soils
tools, flats and other equipments
C) Cultural Practices
a) Pre-season clean up
Under protected environment monoculture is suggested, however, if one has to go for polyculture then avoid staggered planting
b) Inspection upon arrival
• insect-free planting material.
• remove lower or damaged found that populations of greenhouse whitefly (T. vaporariorum),
• number of whiteflies trapped on sticky yellow cards under a UV-absorbing film were 10 - 100 times lower than the number trapped
under regular films.
c) Balanced use of fertilizer
d) Pinching and Pruning
e) Trap crop/Indicator plants
f) Plant Quarantine

11. INTEGRATED PEST MANAGEMENT ..
MONITORING AND SCOUTING:
Yellow sticky cards :
For whiteflies, aphids, thrips and leaf-miner adults, yellow sticky cards (4″x12″ or 8″x12″) are an
excellent supplement to pest observation in the protected environment.
Place the cards in a vertical orientation, so that the card is level with the new plant growth at the top of
the crop. (White, J. 2014)
1-2 yellow sticky cards per 100 square meter of floor area are used.
General “action threshold” pest densities such as 0.5 whiteflies/sticky card/day for young crops, or 2
whiteflies/sticky card/day for mature crops . (White, J. 2014)
Change the cards when more than 60-70 per cent of the area is covered by trapped insect
Scout the crop on a regular basis and at least 1-2 per cent of the total plants should be inspected at
weekly interval.

12. INTEGRATED PEST MANAGEMENT ..
CONTROL
 Biological control:
 Parasitoids:
 Encarsia formosa is a parasitoid wasp that lays its eggs in whitefly nymphs,
 Eretmocerus eremicus is another parasitoid that is commercially available, perform
better at higher temperatures
 papaya (Carica papaya L.) is a host of the relatively host specific whitefly,
Trialeurodes variabilis (Lourencao et al., 2007), which was reported to be highly
parasitized by the parasitoid, Encarsia Sophia (Gerling et al., 2001)
 predators:
 Delphastus catalinae (tiny black lady bird beetle (1/15 inch) that consumes whitefly
eggs and nymphs), a predatory mite, Amblyseius swirskii a predatory mirid
bug, Dicyphus hesperus
 Nematodes: Steinernema feltiae
 Entomopathogenic organisms
 Fungi: Beauveria bassiana, Paecilomyces fumosoroseus and Lecanicillium lecanii,
Verticillium lecanii have been shown a high potential for whitefly control.
 V. lecanii has been successfully used against greenhouse infestations of whitefly,
aphids and thrips
Encarsia formosa adult female
inserting its ovipositor in a
whitefly nymph.

13. INTEGRATED PEST MANAGEMENT ..
• Bio pesticide
• azadirachtin(0.0025%) and mineral oil (0.5%) could be used in rotational manner to manage insecticide resistance
problems that might develop in greenhouses
• Chemical control
• Abamectin (0.004%), acetamiprid (0.008%), buprofezin(0.02%), and bifenthrin (0.004%) can effectively manage
immatures and adults of the whitefly T. vaporariorum infesting tomato in greenhouses
• soil-applied imidacloprid can provide up to 11 weeks control of the greenhouse whitefly adults and nymphs on
strawberry (JL Bi etal., 2007)
Kashyap etal., (2016)

14. THANK YOU