Table Of ContentXavier Fauvergue · Adrien Rusch
Matthieu Barret · Marc Bardin
Emmanuelle Jacquin-Joly
Thibaut Malausa · Christian Lannou
Editors
Extended
Biocontrol
Extended Biocontrol
(cid:129)
Xavier Fauvergue Adrien Rusch
(cid:129)
Matthieu Barret Marc Bardin
(cid:129)
Emmanuelle Jacquin-Joly Thibaut Malausa
Christian Lannou
Editors
Extended Biocontrol
Editors
XavierFauvergue AdrienRusch
ISA.INRAE,CNRS,UCA SAVE.INRAE,BordeauxSciencesAgro,ISVV
SophiaAntipolis,France Villenaved’Ornon,France
MatthieuBarret MarcBardin
IRHS.UnivAngers,InstitutAgro, PathologieVégétale.INRAE
INRAE,SFRQUASAV Montfavet,France
Angers,France
EmmanuelleJacquin-Joly ThibautMalausa
iEES-Paris.INRAE,CNRS,IRD, ISA.INRAE,CNRS,UCA
SorbonneUniv,UnivParis, SophiaAntipolis,France
UnivParisEstCréteil
Versailles,France
ChristianLannou
SPE.INRAE
SophiaAntipolis,France
[email protected]
ISBN978-94-024-2149-1 ISBN978-94-024-2150-7 (eBook)
https://doi.org/10.1007/978-94-024-2150-7
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Preface
Strictly speaking, biological control, or biocontrol, is defined as the use of living
organisms to reduce the abundance or impact of pests. These living organisms,
known as biocontrol agents, are natural enemies or antagonists of the target pests
andincludearthropods,nematodes,fungi,oomycetes,bacteriaandviruses.Theyare
deployed according to three general strategies: importation, augmentation (which
includesinundationandinoculation)andconservation.Inthisbook,weputforward
abroaderdefinitionofbiocontrolthatalsoembracestheproductsoflivingorganisms
aswellassterileorincompatibleinsectpests.Toavoidanyambiguity,wehaveused
theterm“extendedbiocontrol”inthetitleandwhereverneededtoaccountforthese
inclusions. Extended biocontrol encompasses biological control sensu stricto,
autocidalcontrol,andtheuseofsemiochemicalsandplant-derivedbiopesticides.
SophiaAntipolis,France XavierFauvergue
Villenaved’Ornon,France AdrienRusch
Angers,France MatthieuBarret
Montfavet,France MarcBardin
Versailles,France EmmanuelleJacquin-Joly
SophiaAntipolis,France ThibautMalausa
SophiaAntipolis,France ChristianLannou
v
Introduction
Thefieldofbiologicalcontroliscurrentlyundergoinganexpansionthatiscloselytied
toourgrowingawarenessoftheproblemsassociatedwithmassivesyntheticpesticide
use inagriculture and efforts toidentifyalternatives. And yet,the ideaofbiological
controlitself–usingthetoolsprovidedbynaturetomanagecropparasitesandpests–
isnotnew.Themainreasonswhy“biological”approachesarenotmorewidelyused
inagriculture inindustrializedcountries are thatsynthetic pesticideshavelongbeen
cheap,easytoaccessandeffective,anduserswerelargelyunawareoftheirnegative
impacts on the environment, biodiversity and even human health. But things have
changed,especiallyinEurope,andmanycountrieshavebegunenactingmoreproac-
tive policies. This has helped bring sustainable farming systems and environmental
protectionbacktotheforewhilepushingagriculturalresearchtoexplorenewpaths.
Areasthathadpreviouslybeenoverlookedarenowbeingreconsideredandwillsurely
becomethecornerstonesofcropprotectioninthefuture.
Thisbookroundsupthelatestresearchinbiologicalcontrolandcropprotection
methods based on natural pest control, which we will refer to here as “extended
biocontrol”.Theauthorstakeacriticallookatthevarioussolutionsthatare,orwill
onedaybe,availabletoagriculture.Thebookalsoexplorestheunderlyingconcepts
thatarekeytounderstandingandmakinguseofbiologicalinteractionsincropping
systems as well as the possible applications under consideration or already being
used in the field. Readers should note that there are other approaches to crop
protection, such as the use of resistant plants or preventive measures, that are not
coveredinthisbook.
Crops Need to Be Protected – But Differently
Humans and other organisms, including pathogens and insects, have likely been
competingforcropssincetheadventofagriculture(Stukenbrocketal.2007).Inthe
West, the oldest references to plant protection methods date back to the Romans
vii
viii Introduction
(Cato the Elder ca. 160 BC). In Europe, the modern history of crop protection
emerged in the nineteenth century following the appearance of major pests and
diseases: the introduction of grapevine powdery mildew from 1845 and the
demonstration – andthen broad use– ofsulphurto control it, and theintroduction
of grapevine downy mildew in 1878 and the development of Bordeaux mixture in
theearly1880s.
However,theEuropeanagriculturalworldexperiencedaseachangejustafterthe
Second World War with a newfound political drive to intensify production to feed
the continent’s population. Agricultural research efforts steadily increased yields;
France, for example, achieved food self-sufficiency in the 1970s and was able to
begingeneratingtradesurpluses.Thisextraordinaryprogresswasmadepossibleby
radical shifts in farm structure, greater mechanization, access to abundant fertiliza-
tionandintensivegeneticselectioneffortstoobtainmoreproductivecropvarieties.
Intermsoffoodsecurity,thisagriculturalintensificationwasasuccess.However,
italsomadecropsmorevulnerabletopests.Merelygrowingdensecropsofthesame
species opened the door to epidemics and the proliferation of pests. Organizing
farms into large fields of genetically homogeneous crops and applying generous
quantitiesofnitrogenfertilizersonlyworsenedthings.Thesolutiontotheproblem,
initially solved by systematically applying chemical pesticides, created new prob-
lemsthatarenowuptoustotackle.
Theuseofsyntheticpesticidesinagriculture–andmorespecifically,herbicides
and insecticides – rose following the Second World War. Synthetic fungicides
appeared in the 1960s, and became more widespread in the 1970s with formulas
containing systemic and curative active ingredients. These increasingly efficient
productssuccessfullymanagedpestsanddiseaseswhileallowingthenewvarieties
toreachtheirfullyieldpotential.Theymadeintensiveproductionsystemspossible
whilelimitinghealthrisks.Butforfarmers,pesticideusealsobecomesomethingofa
crutch,andsomeanalystswouldevensayanaddiction(Bonnefoy2012;Valo2012).
Theirheavyuseledtotwomajorproblems:first,theselectionofresistanceintarget
pests,andsecond,majorenvironmentalandhealthimpacts.
Although the environmental and health impacts related to pesticides have
attracted considerable media attention in recent years, we have known about these
issues for some time. Already in 1962, American biologist Rachel Carson shone a
spotlight on the problem with her book Silent Spring. Little by little, the public
authorities started banning the most dangerous substances (e.g. organochlorine
insecticides like DDT). Even more recently, the discovery of the sublethal effect
ofneonicotinoidsonbees(Henryetal.2012)ledtheauthoritiestotakestepstoban
theuseofsomeoftheseproductsinEurope.
Public attitudes have also changed markedly as of late with regard to pesticide
use, and producers can no longer turn a blind eye. The many press articles on
conflicts between farmers andlocal residents areatellingexample.Consumers are
quitevocalintheirdesireforfreshproducethatisfreeofpesticideresidues,although
general attitudes remain paradoxical: while shoppers are asking explicitly for
untreated food, there is an implicit demand for cheap, perfect-looking fruit on
shopshelves.
Introduction ix
ExtendedBiocontrol:AFreshLookatanAge-OldApproach
Theterm“extendedbiocontrol”usedinthisbookreferstoasetofcroppest-control
methodsbasedonnaturalmechanismsthatgobeyondthoseincludedinthenarrow
definition of biological control. Extended biocontrol includes the use of natural
enemies, microbial control, semiochemicals (such as pheromones) and
biopesticides.
Many of these approaches have been around a long time. The first examples of
biologicalcontrolsupportedbyascientificapproachdatebacktothelatenineteenth
and early twentieth centuries (see Chaps. 3 and 4). Additionally, farmers have
always used biological pest control methods on an empirical basis in subsistence
andsmall-scalefarming.TheCreolegarden,mentionedinChap.20,isanexcellent
exampleofthis.Bycapitalizingonnaturalmechanismstoprotectplants,thegoalis
togivemodernagriculturenewwaystousemethodsthathadfallenbythewayside
whenwetriedtoignoretheearth’snaturalchecksandbalancesthroughfertilization
andchemicalprotection.Whetherinspirationcomesfromobservingnature(youcan
see ladybirds eating aphids right in your own garden) or from analysing farmers’
first-hand knowledge (e.g. planting mixtures of mutually beneficial species), the
challenge is to develop targeted academic research on biocontrol approaches with
practical applications for productive agriculture to feed the world and provide a
livelihoodforfarmers’families.Althoughthisischieflyabiologicalandecological
engineering issue, there are also essential sociological and economic dimensions
(presented in Chaps. 18, 19 and 20). We cannot simply substitute biological solu-
tionsforchemicalsolutionsandkeepourcurrentcroppingsystems(see,especially,
Chap. 20). Shifting from chemical to biological solutions will require a total
overhaul of ourfarming systems:they must be redesigned and rebuilt, with proper
supportmeasuresforproducers.
The Biocontrol Arsenal
To get back to the main topic, what exactly are the “natural mechanisms” we are
talkingabout?Chemicalprotectionisbasedonaverystraightforwardidea:youbuy
aproductthatiscompatiblewithastandardsprayer,putonprotectiveclothing,and
apply the product at the recommended dose (while trying not to think too much
aboutthelong-termimpactsontheenvironmentorthepeoplelivingnearyourfield).
By comparison, extended biocontrol offers an array of options, which are all
partially effective and must be used in certain ways. Sometimes, the application
methodsmaystillnotbefullyworkedout.
And yet, these approaches boast some very interesting advantages. One major
problem with chemical pesticides is that the pest populations they are meant to
controlcanquicklydevelopresistance(justlikehowoveruseofantibioticscanlead
tobacterialresistance).Althoughsomequestionsremainaboutthesustainabilityof
x Introduction
extended biocontrol solutions (see Chap. 23), insects rarely develop resistance to
theirpredators.Resistanceinpestsisrelatedtotheirgeneticvariabilityandthelong-
term arms race coevolution with their enemies. Thus, what is problematic for
chemicalpesticidescanbeturnedintoanadvantagehere:biologicalcontrolagents
also have an ability to adapt that can be exploited for sustainable pest control (see
Chap.4).
Moreover,therangeofsolutionsthatareormayonedaybeavailablemeansthat
we can build crop protection systems around different constraints, with certain
beneficial effects materializing once the systems are fully redesigned and the pest
control methods are well mastered. One example is the evolution of greenhouse
farming in the Almeria region of Spain. Following a health scandal linked to the
presenceofunauthorizedpesticideresiduesinpeppers,whichledEuropeanbuyers
toswitchsuppliers,aradicalconversiontobiologicalcontrolwascarriedoutinthis
farming area, leading to the nearly total elimination of chemical control of thrips.
Around 70% of local farmers adopted this approach, versus just 4% in 2006. This
conversionwasaccompaniedbyimprovedtechnicalexpertisethroughtrainingand
financialsupportfromthestate(GlobalG.A.P.2016).However,environmentaland
labourproblemsalsoarosealongwiththisnewformofintensification,servingasa
reminderthatwhileabiologicalapproachtocropprotectionhasundeniableadvan-
tages, it is not intrinsically virtuous (Mandard 2019). Biological control in green-
houseshasalsobeenremarkablysuccessful.Forexample,intheNetherlands,more
than 90% of tomatoes, cucumbers and peppers are grown using integrated pest
management strategies that include biological control methods, resistant varieties
andclimatecontrol.
Thereasonsthatbiological controlingreenhousesissuccessfulhavenothingto
dowith idealisticintentionsonthepart ofprofessionals,who areunwillingtotake
risks on high-value produce when pesticides cost so little. Instead, producers cite
enhanced technical efficiency given the emergence of pesticide resistance, the
possibility of using pollinators in greenhouses, no need for turnaround time or
harvest delays, a lack of phytotoxicity, reduced monitoring and fewer necessary
interventions, lack of risk for workers applying treatments, and consumer expecta-
tions. Biological controlisperceivedas a profitable, efficient systemwith multiple
benefits.Whencombinedwithclimatecontrolingreenhousesandresistantvarieties,
biological control can support a coherent crop protection system in a confined
environment,whichcanbedifficulttoextrapolatetotheopenfield.
This book takes a comprehensive look at the different techniques available for
extended biocontrol, which includes classical, augmentative and conservation bio-
logical control. Extended biocontrol also encompasses the sterile insect technique;
theuseofmicroorganismsthatpromoteplanthealthalongwiththoseformicrobial
pest control; semiochemicals that can trick insects’ senses; and various natural
substanceswithadirectactiononpests(biopesticides).
Introduction xi
The Different Types of Biological Control
Thefirstpartofthisbookdealswiththeuseofnaturalenemies.Afterareviewofthe
generalconceptsandunderlyingscientificprinciples(Chaps.1and2),thedifferent
practicalapproachesarethenexplained(Chaps.3,4and5).Thesecondpartofthe
book delves into conservation biological control, which relies on natural trophic
interactionsatthelandscapescale(Chaps.6,7and8):here,theaimisnottodeploy
one organism (natural enemy) against another (pest), but rather to support and
encouragenaturalpredatorandparasiterelationsthatlimittheproliferationofcrop
pests.
Classical biological control involves identifying a natural enemy, usually from
the pest’s native range, and then releasing it into the area to be protected. This
approach is mainly used against invasive pests that have been accidentally intro-
duced.Theprocess(Chap.3)entails:
(cid:129) conductinganinventoryofthenaturalenemiesofthepestinitsnativerange,
(cid:129) characterizingthespecies(whichmayleadtoathoroughreviewofacomplexof
morphologicallysimilarspecies,butwithdifferenthostranges;seeChap.1),
(cid:129) characterizingthenaturalenemy’seffectivenessandhostrange,
(cid:129) assessingthepossibilitiesofproducingthenaturalenemyandsettinguprearing
facilities,
(cid:129) releasingthenaturalenemyinthefieldandmonitoringitsdynamics.
Classicalbiologicalcontrolhasseveralmajoradvantages.Asuccessfulintroduction
will have a sustained effect and not lead to significant additional costs, and the
natural enemy can develop in hard-to-access areas. When everything comes
together,it can be remarkably effective. However, this approach does notgenerate
commercial profits and it must be implemented by public organizations with the
supportofrelevantpartnersandsectors.Onegoodexample,asexplainedinChap.3,
is the introduction of the parasitoid wasp Torymus sinensis to control the oriental
chestnutgallwasp.
Augmentative biological control, described in Chap. 4, is based on the mass
production of natural enemies that are then released in large numbers in a specific
area,suchasagreenhouse,toachieveimmediateresults.Itworkswellonendemic
pestsandcanreplaceclassicchemicalpesticides.Thisapproachandthemarketforit
aregrowingconsiderably,buteffortsaremainlyfocusedonhighvalued-addedcrops
grownundercover.Thenumberofnewcommercializednaturalenemiesincreased
sharplythroughthe1990sandthendeclinedafter2000,partlyduetomorerestrictive
regulations on importing and introducing exotic species (based on the Nagoya
Protocol on Access and Benefit-sharing, which followed on from the Convention
onBiologicalDiversityandenteredintoforceon12October2014).Researchefforts
have been refocused on natural enemies that are endemic to the area in question,
ratherthanrelyingsoheavilyonexoticspecies.
Atfirstglance,thesebiologicalcontrolapproachesmayseemrelativelyconven-
tional,butthevariouschaptersdevotedtothem,aswellasChaps.18,19,20and21,
