Botanical biopesticides- Azadirachta, Pongamia and AnnonaNotes.pdf

Plant based biopesticides

1. Azadirachta,Pongamia,andAnnona

2. Introduction
Biopesticidesarenaturalplant-derivedcompoundsusedtocontrolpests,diseases,and
weeds.
Theyareeco-friendly,biodegradable,andsaferthansyntheticpesticides.
Manyplantsproducesecondarymetaboliteswithinsecticidal,fungicidal,ornematicidal
activity.
Importantexamples:Azadirachta(Neem),Pongamia(Karanj),andAnnona(Custardapple).
Azadirachtaindica(Neem)
Source
BelongstofamilyMeliaceae.
NativetoIndia,widelydistributedintropicalregions.
Seeds,leaves,bark,andoilarerichinactivecompounds.
ActivePrinciple
Azadirachtin(mostimportant)–alimonoid.Othercompounds:nimbin,salannin,meliantriol.
ModeofAction
Insectgrowthregulator(IGR):disruptsmoltingandmetamorphosis.
Feedingdeterrent/antifeedant:insectsstopeatingleavestreatedwithneem.
Ovipositiondeterrent:insectsavoidlayingeggsontreatedsurfaces.
Sterilityinduction:reducesreproductiveabilityofinsects.
Repelsmanyinsectsduetobittertasteandodor.
Uses
Controls>200insectspecies(e.g.,aphids,whiteflies,leafminers,caterpillars).
Effectiveagainstfungi(powderymildew,rusts)andnematodes.Usedinstoredgrain
protection(reducesinfestationofweevilsandbeetles).
Neemcake(seedresidueafteroilextraction)actsasasoilamendmentandnematicide.
Pongamiapinnata(Karanj/IndianBeech)
SourceBelongstofamilyFabaceae(Leguminosae).NativetoIndiaandSoutheastAsia.Seeds
yieldpongamiaoil,traditionallyusedforlamps,soap,andmedicine.

3. ActivePrinciple
Karanjin(flavonoidfuranoflavonoid).Pongamolandotherminorcompounds.
ModeofAction
Actsascontactpoisonandrepellentagainstinsects.
Showsantifeedantactivity.Exhibitsantimicrobialandnematicidalproperties.
Workssynergisticallywithotherbiopesticides.
Uses
Effectiveagainstdefoliators,caterpillars,aphids,thrips,andmites.Azadirachtaoilsprays
usedinhorticulturecropsforpestmanagement.
Seedcake(afteroilextraction)usedasorganicfertilizer+nematicide.
Actsagainstfungalpathogens(Alternaria,Fusarium,Aspergillus).
Oftenmixedwithneemoilforimprovedefficacy.
Annonaspp.(CustardApple/Soursop)
Source
BelongstofamilyAnnonaceae.
Commonspecies:Annonasquamosa(Custardapple),Annonamuricata(Soursop),Annona
reticulata.
Seedsandleavesarerichinpesticidalcompounds.
ActivePrinciple
Acetogenins(annonacin,squamocin,muricatacin).
Alkaloids,flavonoids,tannins.
ModeofAction
MitochondrialcomplexIinhibitor→disruptsenergyproductionininsectcells.
Actsasstomachpoison,contactinsecticide,andovicidalagent.
Toxictoinsectnervoussystem.
Uses
Seedextractseffectiveagainstmosquitolarvae(Culex,Aedes,Anopheles).

4. Controlsstoredgrainpests(weevils,beetles).
Leafextractsusedagainstaphids,whiteflies,andcaterpillars.
Showsantifungalandantibacterialactivity.
Potentialuseinvectorcontrolprograms.
AdvantagesofBotanicalBiopesticides
Biodegradableandeco-friendly.
Safertohumansandnon-targetorganisms.
Reducepesticideresiduesinfood.
SuitableforIntegratedPestManagement(IPM).
Canbepreparedatfarmer’slevel(low-cost).
Limitations
Lowerpersistence(needfrequentapplication).Variationinefficacyduetoenvironmental
conditions.
Large-scaleproductionandstandardizationarestilldeveloping.
Sometimeslesseffectivethansyntheticpesticides.