Table Of ContentSERIES EDITORS
KARL MARAMOROSCH
Rutgers University, New Brunswick, New Jersey, USA
THOMAS C. METTENLEITER
Friedrich-Loeffler-Institut, Federal Research Institute for
Animal Health, Greifswald – Insel Riems, Germany
FREDERICK A. MURPHY
University of Texas Medical Branch, Galveston, Texas, USA
ADVISORY BOARD
DAVID BALTIMORE
PETER C. DOHERTY
HANS J. GROSS
BRYAN D. HARRISON
BERNARD MOSS
ERLING NORRBY
PETER PALUKAITIS
JOHN J. SKEHEL
MARC H.V. VAN REGENMORTEL
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CONTRIBUTORS
YehezkelAntignus
PlantPathologyandWeedResearchDepartment,ARO,TheVolcaniCenter,BetDagan,
Israel
FabrizioCillo
IstitutodiVirologiaVegetale,CNR,Bari,Italy
MasarapuHema
DepartmentofVirology,SriVenkateswaraUniversity,Tirupati,India
JohnH.Hill
DepartmentofPlantPathologyandMicrobiology,IowaStateUniversity,Ames,Iowa,USA
Jacquelined’A.Hughes
AVRDC—TheWorldVegetableCenter,Shanhua,Tainan,Taiwan,P.R.China
RogerA.C.Jones
SchoolofPlantBiologyandInstituteofAgriculture,UniversityofWesternAustralia,
Nedlands,andDepartmentofAgricultureandFood,SouthPerth,WesternAustralia,
Australia
NikolaosKatis
FacultyofAgriculture,ForestryandNaturalEnvironment,SchoolofAgriculture,Plant
PathologyLab,AristotleUniversityofThessaloniki,Thessaloniki,Greece
LawrenceKenyon
AVRDC—TheWorldVegetableCenter,Shanhua,Tainan,Taiwan,P.R.China
SanjeetKumar
AVRDC—TheWorldVegetableCenter,Shanhua,Tainan,Taiwan,P.R.China
SafaaG.Kumari
InternationalCentreforAgriculturalResearchintheDryAreas(ICARDA),Tunis,Tunisia
MosheLapidot
InstituteofPlantSciences,VolcaniCenter,ARO,BetDagan,Israel
P.LavaKumar
InternationalInstituteofTropicalAgriculture,Ibadan,Nigeria
Herve´ Lecoq
INRA,UR407,StationdePathologieVe´ge´tale,MontfavetCedex,France
JamesP.Legg
InternationalInstituteofTropicalAgriculture,DaresSalaam,Tanzania
KhaledM.Makkouk
NationalCouncilforScientificResearch,Beirut,Lebanon
PeterPalukaitis
DepartmentofHorticulturalSciences,SeoulWomen’sUniversity,Seoul,RepublicofKorea
ix
x Contributors
BasavaprabhuL.Patil
NationalResearchCentreonPlantBiotechnology,IARI,PusaCampus,NewDelhi,India
JaneE.Polston
DepartmentofPlantPathology,UniversityofFlorida,Gainesville,Florida,USA
DodlaV.R.Reddy
FormerlyPrincipalVirologist,ICRISAT,Patancheru,Hyderabad,India
MargaretG.Redinbaugh
USDA,AgriculturalResearchService,Corn,SoybeanandWheatQualityResearchUnit
andDepartmentofPlantPathology,OhioStateUniversity-OARDC,Wooster,Ohio,USA
PothurSreenivasulu
FormerlyProfessorofVirology,SriVenkateswaraUniversity,Tirupati,India
Wen-ShiTsai
AVRDC—TheWorldVegetableCenter,Shanhua,Tainan,Taiwan,P.R.China
JoopA.G.vanLeur
NSWDepartmentofPrimaryIndustries,TamworthAgriculturalInstitute,NewSouth
Wales,Australia
StevenA.Whitham
DepartmentofPlantPathologyandMicrobiology,IowaStateUniversity,Ames,Iowa,USA
WilliamM.Wintermantel
USDA-ARS,Salinas,California,USA
Jose´ L.Zambrano
InstitutoNacionalAuto´nomodeInvestigacionesAgropecuarias(INIAP),Programa
NacionaldelMa´ız,Quito,Ecuador
PREFACE
Cropplantssufferfromanumberofabioticandbioticdiseaseswithsomeof
themcausinghigh-yieldlosses.Itisgenerallyacceptedthatviraldiseasesrank
second after fungal plant diseases in terms of economic losses they cause
globally. So far, morea thousand viral diseaseshave been describedworld-
wide and currently new viruses are characterized due to the new technol-
ogies. Viruses are intercellular parasites which depend on the host plant
cell machinery for their replication. Therefore, they cannot (at present)
be controlled by chemical pesticides as is practiced for fungal or bacterial
plant diseases. Management of viral diseases relies on the prevention
measures.Thecurrentmethodsformanyimportantcrops,boththoseprop-
agatedbyseedandthosepropagatedvegetatively,willbeoutlined,describ-
ing the most up-to-date state of knowledge. The chapters were written by
experts who have been working for years with the respective crop(s).
Eachchapterdealingwithaspecificoranumberofrelatedcrops(e.g.,Cit-
rus) summarizes the most important viruses infecting the crop, their epide-
miology and ecology, and finally measures for their control. Also, chapters
dealingwithnovelstrategiesconcerningcontrolofair-bornevirusesinthe
fieldandingreenhouseswillbeoutlined.Transgenicresistanceanoveland
promisingapproachwillhelptoincreasefoodproduction,oncesomepublic
phobia will diminish.
The information on the control of plant viruses in the various crops
necessitates splitting it into two volumes. The present volume contains
two general chapters and chapters on control of crops propagated by seed,
such as cucurbits, legumes, maize, and pepper. The following one will be
centeredoncontrolinvegetativepropagatedcrops,suchasberrycrops,cas-
sava, citrus, grapevine, and pome and stone fruits.
WewouldliketoexpressourgratitudetoProf.KarlMaramoroschwho
encouraged us to proceed with the subject and Ms. Helene Kabes and her
staff who helped us with the technical details.
Finally, we hope that this book will be of interest to plant virologists,
horticulturists, and practitioners and will further contribute to the control
of viral diseases and minimize the losses they cause to the crops.
GAD LOEBENSTEIN AND NIKOLAOS KATIS
August 2014
xi
CHAPTER ONE
Management of Air-Borne Viruses
“ ”
by Optical Barriers in Protected
Agriculture and Open-Field Crops
Yehezkel Antignus*,1
*PlantPathologyandWeedResearchDepartment,ARO,TheVolcaniCenter,BetDagan,Israel
1Correspondingauthor:e-mailaddress:[email protected]
Contents
1. Introduction 2
2. TheInsectsVisionApparatus 2
2.1 UVvisionandinsectsbehavior 3
3. UseofUV-AbsorbingCladdingMaterialsforGreenhouseProtectionAgainst
theSpreadofInsectPestsandVirusDiseases 7
3.1 SpectraltransmissionpropertiesofUV-absorbingcladdingmaterials 7
3.2 EffectofUV-absorbingfilmsontheimmigrationofinsectpestsinto
greenhouses 9
3.3 EffectofUVfiltrationonthespreadofinsect-vectoredvirusdiseases 11
3.4 EffectofUVfiltrationoncropplants 12
3.5 EffectofUVfiltrationonpollinators 14
3.6 EffectofUVfiltrationoninsectnaturalenemies 16
3.7 EffectofUV-absorbingscreensontheimmigrationofinsectpestsinto
greenhouses 17
3.8 ModeofactionofUV-absorbinggreenhousecladdingmaterials 18
4. StickyTrapsforMonitoringandInsectsMassTrapping 19
5. SoilMulches 20
6. ReflectiveandColoredShadingNets 23
7. ReflectiveFilmsFormedbyWhitewashes 24
8. ProspectsandOutlooks 26
References 26
Abstract
Theincurablenatureofviraldiseasesandthepublicawarenesstotheharmfuleffectsof
chemicalpestcontroltotheenvironmentandhumanhealthledtotheriseoftheinte-
gratedpestmanagement(IPM)concept.Culturalcontrolmethodsservetodayasacen-
tral pivot in the implementation of IPM. This group of methods is based on the
understandingofthecomplexinteractionsbetweendiseaseagentsandtheirvectors
aswellastheinteractionsbetweenthevectorsandtheirhabitat.Thischapterdescribes
AdvancesinVirusResearch,Volume90 #2014ElsevierInc. 1
ISSN0065-3527 Allrightsreserved.
http://dx.doi.org/10.1016/B978-0-12-801246-8.00001-9
2 YehezkelAntignus
asetofculturalcontrolmethodsthatarebasedonsolarlightmanipulationinawaythat
interferes with vision behavior of insects, resulting in a significant crop protection
againstinsectpestsandtheirvectoredviruses.
1. INTRODUCTION
Insect-borneplantvirusesmaycauseseverelossestomanyannualand
perennialcropsofahigheconomicvalue.Insectvectorsofplantvirusesare
foundin7ofthe32ordersoftheclassInsectaandarethereforeresponsible
for severe epidemics that form a threat to the world’s agricultural industry.
Insect vectors transmit plant viruses by four major transmission modes that
are supported by a number of viral and insect proteins (Raccah & Fereres,
2009).Theobligatoryparasitismofplantvirusesandtheirintimateintegra-
tionwithintheplantcellrequiresanindirectapproachfortheircontrol.This
chapter will focus on the use of light manipulation to affect insects vision
behaviorinawaythatinterfereswiththeirflightorientation,theirprimary
landing on thecrop,and thesecondarydispersalwithin thecrop.Manipu-
lationoflightsignalssimultaneouslydiminishestheinsectimmigrationinto
thecropandreducesfeedingcontactsbetweentheinsectvectorandthehost
plant, thus lowering significantly virus disease incidence.
2. THE INSECTS VISION APPARATUS
Insects perceive light through a single pair of compound eyes which
facilitate a widefield of vision. The basicunit of the compound eyes is the
ommatidiumwhichrestsonabasementmembrane.Thecorneagencellsare
locatedatopalongretinulaformedbylongneuronsandsecondarypigment
cells.Acrystallineconelieswithinthecorneagencells.Thedorsalsurfaceof
theommatidiumiscoveredwiththecorneallenswhichisaspecializedpart
of insect cuticle. Part of each retinula cell is a specialized area known as a
rhabdomere.Anerveaxonfromeachretinulacellprojectsthroughthebase-
ment membrane into the optic nerve. Ommatidia are functionally isolated
because the retinula cells are surrounded by the secondary pigment cells
(Diaz & Fereres, 2007).
Vision involves the transduction of light energy into a bioelectric signal
within the nervous system. The first events in this process take place in the
retinula cells. The fine structure of rhabdomeres consists of thousands of
closelypackedtubules(microvilli).Thevisualpigmentsoccurmainlyinthese
ManagementofAir-BorneViruses 3
rhabdomericmicrovilli.Ithasbeensuggestedthatthesmalldiameterofeach
microvillusinhibitsfreerotationofvisualpigments.Thisspecificorientation
may be the molecularbasis ofinsects’sensitivity to polarized light.Photobi-
ologicalprocessesintheinsecteyeoccurinanarrowbandoftheelectromag-
netic spectrum between 300 and 700nm. Visual pigments initiate vision by
absorbing light in this spectral region. These pigments are a class of
membrane-boundproteinsknownasopsinsthatareconjugatedwithachro-
mophore. Visual pigments whose chromophoreis retinalarecalled rhodop-
sins. The visual pigments of all invertebrates, including insects, crustaceans,
and squids, are all rhodopsins. According to which parameter of the light is
being used or what information is extracted from the primary sensory data,
visionisoftendividedintosubcategorieslikepolarizationvision(Wehner&
Labhart, 2006), color vision, depth perception, and motion vision (Borst,
2009).Polarizationarisesfromthescatteringofsunlightwithintheatmosphere
enablingtheinsecttoinferthelocationofthesuninthesky.Thepolarization
planeisdetectedbyanarrayofspecializedphotoreceptors(Heinze&Homberg,
2007). Many insects can discriminate between light wavelength (color)
(Fukushi,1990)itscontrastandintensity.Motionsignalsarealsopartofvision
cuesthatserveasarichinformationsourceontheenvironmentinwhichthe
insectisacting(Borst,2009;Diaz&Fereres,2007).
2.1. UV vision and insects behavior
Ininsects,thedifferentvisualpigments(opsins)aresegregatedintodifferent
subsetsofcellsthatform theommatidium.In thefruitfly Drosophila,seven
genesencodingdifferentopsinshavebeenidentifiedandsequenced(Hunt,
Wilkie, Bowmaker, & Poopalasundaram, 2001). The ability of insects and
mites(McEnrone&Dronka,1966)toperceivelightsignalsintheUVrange
(300–400nm) is associated with the presence of specific photoreceptors
within their compound eye. UV receptors of the greenhouse whitefly
Trialeurodesvaporariorum(Westwood)asinotherherbivorousinsectsarepre-
sent in the dorsal eye region (Mellor, Bellingham, & Anderson, 1997;
Vernon & Gillespie, 1990). Many insects have two rhodopsins, one with
maximum absorption in ultraviolet wavelengths (365nm) and one with
maximum absorption in the green part of the spectrum (540nm) (Borst,
2009; Matteson, Terry, Ascoli, & Gilbert, 1992). UV component of the
lightspectrumplaysanimportantroleinaspectsofinsectbehavior,includ-
ing orientation, navigation, feeding, and interaction between the sexes
(Mazokhin-Porshnykov, 1969; Nguyen, Borgemeister, Max, & Poehling,
4 YehezkelAntignus
2009; Seliger, Lall, & Biggley, 1994). The involvement of UV rays in the
flightbehaviorofsomeeconomicallyimportantinsectpestshasbeenstudied
by several workers (Coombe, 1982; Issacs, Willis, & Byrne, 1999;
Kring, 1972; Matteson et al., 1992; Moericke, 1955; Mound, 1962;
Vaishampayan, Kogan, Waldbauer, & Wooley, 1975; Vaishampayan,
Waldbauer, & Kogan, 1975).
2.1.1 Effect of UV on insects dispersal and propagation
Whiteflies [Bemisia tabaci (Gennadius)] dispersal pattern under
UV-absorbing films was examined using a release-recapture experiment.
In “walk-in” tunnels covered with a UV-absorbing film and an ordinary
film, a grid of yellow-sticky traps was established forming two concentric
circles: an inner and an external. Under UV-absorbing films, significantly
higher numbers of whiteflies were captured on the internal circle of traps
thanthatontheexternalcircle.Thenumberofwhitefliesthatwerecaptured
on the external circle was much higher under regular covers, when com-
paredwithUV-absorbingcovers,suggestingthatfiltrationofUVlighthin-
dered the ability of whiteflies to disperse in a UV-deficient environment
(Antignus, Nestel, Cohen, & Lapidot, 2001).
Following artificial infestation of pepper plants with the peach aphid
[Myzus persicae (Sulzer)] in commercial tunnels, covered with a
UV-absorbing film, aphid population growth and spread were significantly
lower compared to tunnels covered with an ordinary film. In laboratory
experiments, no differences in development time (larvae to adult) were
observed when aphids were maintained in a UV-deficient environment.
However, propagation was faster in cages covered with the regular film.
Thenumbersofaphidswas1.5–2timesgreaterincagesorcommercialtunnels
coveredwithanordinaryfilm.Inallexperiments,thenumberoftrappedwin-
gedaphidswassignificantlylowerunderUV-absorbingfilms.Itwassuggested
thateliminationofUVfromthelightspectrumreducesflightactivityanddis-
persal of the alate aphids (Chyzik, Dobrinin, & Antignus, 2003).
Mazza, Izaguirre, Zavala, Scopel, and Ballare´ (2002) reported that in
choice situations Caliothrips phaseoli (Hood) (Thysanoptera: Thripidae),
favored areas with ambient UV-A (320–400nm) radiation compared with
areaswherethispartofthelightspectrumwasblocked.Thistypeofbehav-
iorwasexplainedbytherelativelybroadgapbetweenthepeaksensitivities
ofthephotoreceptorsthatareresponsibleforsensingtheUVrange(365nm)
and the visible light (540nm). It was assumed that under UV-deficient
environment formed by the photoselective film, UV receptors are not
ManagementofAir-BorneViruses 5
stimulated by the ambient light, lacking the short wavelength (<400nm)
and thus did not trigger the dispersal flight of thrips. Moreover, it was
hypothesized that if only the 540-nm receptor is activated, thrips should
be unable to discriminate colors but only light brightness because at least
stimulation of two receptors is essential for color vision, and blue and UV
are of special importance regarding color opponency mechanism
(Doring & Chittka, 2007). In large-scale dispersal experiments with
Frankliniellaoccidentalis[westernflowerthrips(WFTs)],plantsorbluesticky
cardswerearrangedinconcentriccirclesaroundasourceplantattherelease
point.DispersaloftheWFTtendedtoexhibitreduceddispersalfromsource
plants under UV-deficient conditions (Kigathi & Poehling, 2012).
2.1.2 UV stimulated phototaxis of insects
The UV range (360–400nm) forms a strong stimulus for whiteflies to fly;
e.g., the greenhouse whitefly, T. vaporariorum, took off more readily and
walked faster when exposed to light of wavelengths under 400nm than
when exposed to that between 400 and 500nm (Coombe, 1981). Similar
photosystems and effects of UV light were suggested for aphids and thrips
(Kring,1972;Mattesonetal.,1992).MonochromaticUVlampsinaflight
chamberservedtostudytheattractionofB.tabacitodistinctwavelengthsin
theUV-AandUV-Cpartsofthespectrum.Whiteflieswereattractedsimilar
to light source emitting at 366 and 254nm (Antignus, Mor, Ben Joseph,
Lapidot,&Cohen,1996).PreferenceforricherUVenvironmentshasbeen
shown for the whiteflies B. argentifolii (Bellows & Perring) and
T. vaporariorum, when tested in choice situations (Costa & Robb, 1999;
Costa, Robb, & Wilen, 2002; Doukas & Payne, 2007b; Mutwiwa et al.,
2005). A striking demonstration of the effect of UV phototaxis on aphids
andwhitefliesoccursingreenhouseswithroofarchesthatarecoveredalter-
nately,withaUV-transmittingfilmandaUV-absorbingfilm.Incaseswhere
suchgreenhousesareinvadedbyvirusborninsects,alltheplantsunderthe
UV-transmitting film become infected, while plants under the
UV-absorbing film remain totally virus free (Y. Antignus, unpublished)
(Fig. 1.1). This dramatic scenario is a consequence of the fact that when
an insect is in a choice situation, it will be attracted always to a UV-rich
environment.
Inchoicesituations,Ceratothripoidesclaratris(Shumsher)thripsexhibiteda
clearpreferencetoflytowardroomsenlightenedwithhigherUVintensities,
whileitavoidsgreenhouseconstructionswithlowinternalUVradiation,as
initially shown by Kumar and Poehling (2006). Costa and Robb (1999)
