IPM - Whitefly

IPM of whitefly under greenhouse conditions in Jordan

1. WHITEFLY

3. Adults on the lower surface

4. Whiteflies
adults on the lower surface of cucumber leaf

5. Whitefly
Order Hemiptera
Suborder Homoptera
Family Aleyrodidae
–Sweet potato whitefly, Bemisia tabaci
–Greenhouse whitefly, Trialeurodes
vaporariorum
–Silverleaf whitefly, Bemisia argentifolii

6. SweetpotatoWhitefly
Bemisia tabaci

7. Biology & Lifecycle:
–Adults prefer the undersides of leaves, especially the
uppercanopy.
–Females produce about 160 eggs, on the undersides
of leaves.
–Upon hatching, the 1st instar nymph or “crawler”
moves about the leaf in search for a place to insert its
needle-like mouthparts into the plant to suck up plant
phloem.
–Large quantities of sweet liquid waste or honeydew
are excreted by nymphs which supports the growth of
black sooty mold fungi.
–Complete development takes from 2.5 to 7 weeks
depends on temperature.

8. Adult:
–About0.8mmlongwithtwopairsofwhitewingsheld
roof-likeoverthecreamcoloredbody.
–Thewhitecolorisduetoacoveringofpowderywax.
Malesaregenerallyabitsmallerthanfemales.
Nymphs :
–Onlythe1stinstar(0.3mm)hastinylegsand
antennae,laterinstarsareimmobilecleartowhitish
withtwoyellowpatchesontheposteriorend.
–Redeyespotsdevelopinthefinal4thinstar/”pupa”.
–Nymphalappearancedependssomewhatonhostleaf
surface,flatwithfewspinesonsmoothleaves,more
roundedwithmorespinesonhairyleaves.

9. Trialeurodes vaporariorumversus
Bemisia tabaci
Trialeurodes vaporariorum:
–Adult:
ThewingsofTrialeurodesare
heldnearlyparalleltotheleafand
covertheabdomenwhenthe
adultisatrest.
–Eggs:
Femalesoccasionallylayeggsin
circlesontheundersidesof
leaves.
–Pupalstage:
isthemostimportantfor
determiningwhiteflyspecies
identification.Greenhousewhitefly
pupaeareovalandhavevertical
sides,givingthepupaacakelike
appearancefromtheside.Along
theperimeteroftheuppersurface
isafringeoffilamentsand
relativelylargewaxfilaments
projectabovetheuppersurfaceof
thebody.
Bemisia tabaci:
–Adults:
Wings are held at the sides of
the body, partially exposing
the back of the abdomen
when the adult is at rest.
–Eggs:
Eggs are not laid in a circular
pattern, are partially inserted
into the leaf, and remain
yellowish until hatching.
–Pupal stage :
pupae are ovoid, with a
slightly pointed hind end and
red eye spots. The pupa is
flat and does not have a
marginal fringe of filaments.

10. Bemisia tabaci

11. Immobile 2 nd or 3 rd instar nymph

12. Sweetpotato whitefly nymphs and
pupae

13. Greenhouse whitefly adults and
pupae.

14. Host Range:
–Over500hostplantspeciesinover74plantfamilies.includingmost
broadleafagronomicandvegetablecropsandmanyornamentalssuch
aspoinsettiaandhibiscus.
–Pepperharborslowerpopulationsthancucurbits&tomatoorother
Solanaceaecrops.
Damage:
–Heavypopulationsaredebilitatingduetosaplossandbuildupofsooty
mold.Feedingbynymphsonleavescausestomatoirregularripening
(TIR),wherefruitdonotcoloruniformlyandexhibitareasofgreenor
whitetissueinternally.
–Anaverageof0.5nymphsperleafduringfruitmaturationmaybe
sufficienttoinduceTIR.
–Thesweetpotatowhiteflyisthekeypestoftomato,primarilyasavector
ofthegeminivirus,Tomatoyellowleafcurlvirus(TYLCV).
–TYLCVcausesseverestunting,chlorosis,cuppingandpuckeringof
leaves,andflowerabortion.Littlefruitissetabovethepointofinitial
infection.
–Theearliertheinfection,thegreatertheimpactonyield.Lossesofup
to90%maybesustainedifplantsshowsymptomswithinthefirstmonth
aftertransplanting

15. TYLCV
A major viral disease transmitted by WF

16. Early symptoms on the tomato

17. Stunting, curling, and small
fruits

18. Tomato Irregular Ripening (TIR) external symptoms

19. Plastic House Scouting Guide
Front entrance
Hind entrance
Middle area
Shady side
Sunny side

20. Monitoring
Scouting:
–Monitorincomingadultswithyellowsticky
cardsandbyobservingadultsbygently
invertingupperleaves.Countnymphsonthe
terminalleafletofleaves(tomato)belowthe
6thnodecountingfromthetop.
ActionThresholds:
–0.5nymphsperterminalleaflet(tomato)or1
adultperleaforplantforTIR.
–ThereisnosetthresholdforTYLCVbecause
incidencedependsontheportionofadults
carryingthevirus.

21. Sticky traps used for monitoring and control of
insect pests

24. CULTURAL CONTROLS
Start Clean:
–Transplants must be free of whiteflies and virus.
TYLCV Tolerant Varieties
Field Manipulations:
–Newlyplantedcropsmustbelocateddistantfromolderplantingsthatmay
serveasasourceofvirusandwhiteflies.
–Exclusionofwingedadultscanbeaccomplishedbycoveringopeningsand
ventswindowsofthegreenhousewithscreensthathaveaporewidthof405
micronsorsmaller.
–Residuesfromspringcropsshouldberemovedandvolunteerscontrolled
duringatleasttwomonthspriortofallplanting.
–Mulch:Reflective(aluminized)mulchmaybeusedtorepelwhitefliesduring
thefirstweeksofplantdevelopment.
–TYLCVinfectedplantsearlyinthecropcycleshouldberemovedfromthe
field,afterbeingsprayedwithaninsecticideeffectiveagainstadults,to
preventdispersalofinfectedwhiteflies.

26. Tunnels

27. Tight Screening (Entrance)

28. DOUBLE DOOR ENTRANCE

29. Screen in the middle

30. Side ventilations were covered with insectproof
neton both lateral sides

31. Chemical Control
–Drenchesofsystemic“neonicotinoid”insecticides(4A*)suchas
imidacloprid(confidor),thiamethoxambeforeandimmediately
followingtransplantingprovidesearlyseasoncontrolthatisessential
formosttomatoproduction.
–Foliarspraysofspiromesifen(Oberon®;)andtheinsectgrowth
regulatorsbuprofezin(Courier®)andpyriproxyfenshouldbeapplied
accordingtothenymphalthreshold.
–Soaps,oils,pymetrozine(FulFill®;9B*)andbroadspectrum
insecticides,aloneortank-mixedwithproductssuchasendosulfan
(cyclodiene).
–OrganophosphatesandpyrethroidsShouldbeappliedaccordingto
theadultthreshold.Thelatterthreegroupsarebestusedtowardthe
endofthecrop.
–Foliarapplicationsofneonicotinoidsshouldnotbemade6weeks
followingsoildrenchesoftheinsecticides.
–Otherproductsofdifferentchemicalclassesshouldberotated.

32. Natural Enemies
–Whiteflieshavemanyeffectivenaturalenemies,
includingparasiticwasps(EncarsiaandEretmocerus
spp.),tomatobugs(Engytatus=Cyrtopeltisspp.),
ladybeetles (Nephaspi and Delphastus
spp.),lacewings(ChrysoperlaandCeraeochrysaspp.)
andmites(Amblyseiusswirskii).
–Naturalenemiesareresponsibleforthelowwhitefly
populationsobservedinweedsandcanhelpcontrol
whitefiesinfieldcropsifbroadspectruminsecticides
areavoided.
–Massreleaseofcertainnaturalenemieshasalso
provedeffectiveingreenhousecrops.

33. Biological Control
Encarsia luteola,a whitefly parasite

34. Eretmocerussp., a whitefly
parasite.

36. Bigeyed bug, Geocorissp

37. Chrysoperla carnea,green
lacewing larva

38. Larva of convergent lady beetle,
Hippodamia convergens

39. Delphastus pusillusadult