Botanicals have been in use for a long time for pest control. A product of species coevolution, these compounds offer many environmental advantages. However, their uses during the 20th century have been rather marginal compared with other bio control methods of pests and pathogens. Improvement in our understanding of plant allelochemical mechanisms of activity offer new prospects for using these substances in crop protection. We examine the reasons behind their limited use and the actual crop protection developments involving plant allelochemicals, namely formulations including bio pesticides of plant origin for organic or traditional agricultures, and improvement of plant resistance to pathogens through identification of genes coding for allelochemicals and stimulation of natural passive and active defenses of the plant. Commercial and regulatory aspects are discussed.

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3. Botanicals - Naturally occurring pesticides that derived
from the plants or plant parts
In the 17th century, pesticidal properties of tobacco
(Nicotiana tabacum L.)
For hundred years, Indian framers have used the neem
tree -‘wonder tree , botanical marvel, gift of nature ,
village pharmacy
Chemical pesticides : commonly used
Undesirable attributes synthetic pesticides
 Botanicals as alternative options
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4. To find out the recent development of botanicalsTo find out the recent development of botanicals
forplant disease controlforplant disease control
ToTo identify problems and the future of developingidentify problems and the future of developing
and using botanicals in agriculture.and using botanicals in agriculture.
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5. A review paperA review paper
Information from the secondary sourcesInformation from the secondary sources
Books, journals, proceedings, reports, publicationsBooks, journals, proceedings, reports, publications
Web browsingWeb browsing
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7. Table 1. Effect of pre and post–inoculation treatment with plantTable 1. Effect of pre and post–inoculation treatment with plant
extracts on the incidence of rice blastextracts on the incidence of rice blast
Table 1. Effect of pre and post–inoculation treatment with plantTable 1. Effect of pre and post–inoculation treatment with plant
extracts on the incidence of rice blastextracts on the incidence of rice blast
Plant speciesPlant species
PDI Values -percent reduction over controlPDI Values -percent reduction over control
Pre-inoculationPre-inoculation Post inoculationPost inoculation
AA BB CC AA BB CC
Abuliton indicumAbuliton indicum 34.334.3 26.626.6 19.819.8 30.230.2 23.323.3 18.818.8
Acalypha indicaAcalypha indica 21.221.2 11.311.3 7.17.1 20.220.2 9.99.9 5.05.0
Azadirachta indicaAzadirachta indica 43.443.4 34.734.7 28.628.6 40.840.8 30.630.6 26.126.1
Boerhavia diffusaBoerhavia diffusa 24.624.6 13.013.0 7.67.6 20.520.5 10.210.2 5.25.2
Clerodendron inermeClerodendron inerme 29.129.1 16.516.5 11.511.5 26.126.1 15.115.1 8.98.9
Cynodon dactylonCynodon dactylon 31,731,7 24.624.6 19.119.1 28.828.8 21.021.0 15.815.8
Cyperous rotendusCyperous rotendus 29.229.2 20.020.0 12.512.5 26.326.3 16.716.7 12.312.3
Lantana camaraLantana camara 26.726.7 14.614.6 8.58.5 23.723.7 12.512.5 6.86.8
Prosphis julifloraProsphis juliflora 54.754.7 47.247.2 37.837.8 51.651.6 46.246.2 30.630.6
Ziyphus jujubeZiyphus jujube 53.253.2 46.546.5 36.636.6 50.850.8 43.343.3 29.829.8
Source : KamalakannanSource : Kamalakannan et elet el., 2001., 2001Source : KamalakannanSource : Kamalakannan et elet el., 2001., 2001
Botanicals for Fungus controlBotanicals for Fungus control
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8. Table 2.Table 2. Fungicidal properties of some of plant products
Source:Source: Cowan, 1999) 8

9. Table 3.Table 3. Mechanisms of action of phytochemicals
Source: Cowan, 1999.
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10. Figure 1. Effect of plant extract on reduction of seed-borne fungi
of onion
Figure 1. Effect of plant extract on reduction of seed-borne fungi
of onion
Source: Kamalakannan et el., 2001 10

11. Botanicals for nematode controlBotanicals for nematode control
Plant extract (leaves)Plant extract (leaves)
Treatments / % mortalityTreatments / % mortality
SS S/2S/2 S/10S/10 S/100S/100
Shatamuli (Shatamuli ( Asparagus officinalisAsparagus officinalis)) 100100 100100 8282 5050
Neem (Neem ( Azadirachta indicaAzadirachta indica)) 100100 9090 7575 5252
Marigld (Marigld (Eucalyptus globulesEucalyptus globules)) 100100 6666 3535 1212
Thankuni (Thankuni (Centella asiaticaCentella asiatica)) 9292 3535 1515 88
Tulsi (Tulsi (Ocimum sactumOcimum sactum)) 8080 4141 2222 99
Pine apple (Pine apple (Ananas comosusAnanas comosus)) 7979 3838 2222 66
Tobacoo (Tobacoo ( Nicotana tabacumNicotana tabacum)) 7878 4343 2222 77
Biskatali (Biskatali (Polygooum hydropiperPolygooum hydropiper)) 7575 4343 2424 77
Pathorkuchi (Pathorkuchi ( Bryophylum calyciumBryophylum calycium)) 7272 4545 2828 66
Citrus (Citrus ( Citrus aurantifoliaCitrus aurantifolia )) 7272 4040 2222 66
Table 4. Effect of plant extract on the mortality of juveniles of Meloidogyne
javanica
Source: Kumar R.P., 2006.Source: Kumar R.P., 2006. 11

12. Table 5. Effect of leaf extracts of dholkalmi on galling of brinjal infected withTable 5. Effect of leaf extracts of dholkalmi on galling of brinjal infected with
MeloidogynejavanicaMeloidogynejavanica
Table 5. Effect of leaf extracts of dholkalmi on galling of brinjal infected withTable 5. Effect of leaf extracts of dholkalmi on galling of brinjal infected with
MeloidogynejavanicaMeloidogynejavanica
MonthMonth ConcentrationConcentration No of gall /g of rootNo of gall /g of root
11stst
monthmonth
controlcontrol 12.50 a12.50 a
SS 5.00 d5.00 d
S/2S/2 7.50 c7.50 c
S/10S/10 9.00 bc9.00 bc
S/100S/100 10.00 b10.00 b
22ndnd
monthmonth
controlcontrol 36.50 a36.50 a
SS 17.75 e17.75 e
S/2S/2 21.5 d21.5 d
S/10S/10 26.25 c26.25 c
S/100S/100 29.25 b29.25 b
33rdrd
monthmonth
controlcontrol 50.00 a50.00 a
SS 24.75 e24.75 e
S/2S/2 31.00 d31.00 d
S/10S/10 36.25 c36.25 c
S/100S/100 39.50 b39.50 b
S = Standard suspension prepared by suspending 25gms of macerated raw plant part in 100 ml. distilled water
Source: Kumar R.P., 2006
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13. Table 6. Efficacy of garlic bulb extracts to control root knotTable 6. Efficacy of garlic bulb extracts to control root knot (Meloidogyne(Meloidogyne
javanicajavanica))
Table 6. Efficacy of garlic bulb extracts to control root knotTable 6. Efficacy of garlic bulb extracts to control root knot (Meloidogyne(Meloidogyne
javanicajavanica))
ConcentrationConcentration
ShootShoot
lengthlength
(cm).(cm).
ShootShoot
weight(g)weight(g)
RootRoot
lengthlength
(cm)(cm)
RootRoot
weightweight
(g)(g)
Gall/g ofGall/g of
rootroot
WaterWater 54.4154.41 93.8893.88 27.5927.59 12.7412.74 51.1551.15
SS 70.3970.39 140.59140.59 43.7043.70 15.3515.35 0.000.00
S/2S/2 70.5970.59 139.21139.21 42.6142.61 14.8014.80 0.000.00
S/10S/10 65.5965.59 128.19128.19 39.3139.31 13.3013.30 1.711.71
S/100S/100 56.4556.45 100.31100.31 28.9928.99 12.5512.55 13.1413.14
Source: Kumar R.P., 2006. 13

14. Botanicals for controlling bacterial diseases
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(Retrieved from:
http://dx.doi.org/10.1100/2012/796472.)
(Retrieved from:
http://dx.doi.org/10.1100/2012/796472.)
Figure 2: Effect of tuber treatment with jute leaf extract and cheerota
plant extract on soft rot disease incidence of potato in storage.

15. Figure 3: Effect of tuber treatment with jute leaf extract and
cheerota plant extract on percentage of loss in weight of potato
in storage condition.
15
(Retrieved from:
http://dx.doi.org/10.1100/2012/796472.)

16. Figure 5: Effect of two botanical extracts on percentage of
disease reduction (PDR) of potato after 22 weeks of inoculation
in storage condition.
16
(Retrieved from:
http://dx.doi.org/10.1100/2012/796472.)

17. ProblemsProblemsProblemsProblems
Lack of research on the active ingredients, pesticide preparations, application
rates and environmental impact of botanical pesticides that are prerequisite for
sustainable agriculture (Buss and Park-Brown 2002).
Commercialization of botanical pesticides may not necessarily benefit the
financially constrained subsistence farmers since the cost of the products may
still render it inaccessible at present.
A challenge that needs to be tackled is dose standardization due to regional
and seasonal variations in plant constitutions and different concentrations of
the active ingredients.
Although botanical pesticides are obtained locally, there is a danger of genetic
erosion when plants are harvested from the wild (Devlin and Zettel 1999).
The toxicological and environmental properties of the compound must be
considered. Simply because a compound is a natural product does not insure
that it is safe. The most toxic mammalian poisons known are natural products
and many of these are plant products.
The relatively short environmental persistence of natural products may be a
problem, because most pesticides must have some residual activity in order to
be effective.
Lack of research on the active ingredients, pesticide preparations, application
rates and environmental impact of botanical pesticides that are prerequisite for
sustainable agriculture (Buss and Park-Brown 2002).
Commercialization of botanical pesticides may not necessarily benefit the
financially constrained subsistence farmers since the cost of the products may
still render it inaccessible at present.
A challenge that needs to be tackled is dose standardization due to regional
and seasonal variations in plant constitutions and different concentrations of
the active ingredients.
Although botanical pesticides are obtained locally, there is a danger of genetic
erosion when plants are harvested from the wild (Devlin and Zettel 1999).
The toxicological and environmental properties of the compound must be
considered. Simply because a compound is a natural product does not insure
that it is safe. The most toxic mammalian poisons known are natural products
and many of these are plant products.
The relatively short environmental persistence of natural products may be a
problem, because most pesticides must have some residual activity in order to
be effective.
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18. The FutureThe Future
 Despite these challenges, this study is suggestible to theDespite these challenges, this study is suggestible to the
use of botanical pesticides by farmers, especially with theuse of botanical pesticides by farmers, especially with the
increased interest in the consumption of organic foodincreased interest in the consumption of organic food
products and awareness to the side effect of syntheticproducts and awareness to the side effect of synthetic
pesticides.pesticides.
 Plants contain a virtually untapped reservoir of pesticidesPlants contain a virtually untapped reservoir of pesticides
that can be used directly or as templates for syntheticthat can be used directly or as templates for synthetic
pesticides.pesticides.
 The success of CH100 liquid, Triact 70, Trilogy 70 andThe success of CH100 liquid, Triact 70, Trilogy 70 and
Garlic pellet for the control of crop diseases indicates that itGarlic pellet for the control of crop diseases indicates that it
is possible to develop a natural plant disease control productis possible to develop a natural plant disease control product
using plant extracts.using plant extracts.
 Botanical pesticides are unique because they can beBotanical pesticides are unique because they can be
produced easily by farmers and small industries (Royproduced easily by farmers and small industries (Roy et alet al..
2005). It may also create scope of employment generation2005). It may also create scope of employment generation
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19.  Extracts of some plant species contain antimicrobial compounds that can beExtracts of some plant species contain antimicrobial compounds that can be
used as alternatives to synthetic pesticides to control of plant pathogensused as alternatives to synthetic pesticides to control of plant pathogens
 Neem, Garlic, Eucalyptus, Ashok and Ginger proved to control different kindsNeem, Garlic, Eucalyptus, Ashok and Ginger proved to control different kinds
of plant pathogenic fungi such asof plant pathogenic fungi such as PyriculariaPyricularia sp.sp. Aspe rg illus nig e rAspe rg illus nig e r,, Pe nicilliumPe nicillium
sp.,sp., FusariumFusarium sp.,sp., Alte rnaria sppAlte rnaria spp .,., Curvularia spp. ,Curvularia spp. , Scle ro tina scle ro tio rumScle ro tina scle ro tio rum
 Shatomuli, Dholkalmi Neem, Marigold, Thankuni, Pineapple, and GarlicShatomuli, Dholkalmi Neem, Marigold, Thankuni, Pineapple, and Garlic
extract proved to reduce plant pathogenic nematodes.extract proved to reduce plant pathogenic nematodes.
 Pro so phis juliflo raPro so phis juliflo ra ,, Acacia arabicaAcacia arabica ,, Ziyphus jujubeZiyphus jujube proved to reduceproved to reduce
Xantho m o nas cam pe strisXantho m o nas cam pe stris andand Lantana cam araLantana cam ara ,, Eucalyptus citro do raEucalyptus citro do ra reducedreduced
Xanhto m o nus o ryzaeXanhto m o nus o ryzae ..
 Spread of some viruses can be reduced by controlling vector by using neem.Spread of some viruses can be reduced by controlling vector by using neem.
 Presently, commercial formulation of botanicals are not sufficient. SomePresently, commercial formulation of botanicals are not sufficient. Some
successful formulations are Garlic Pallet, Allamonda Pellet, Triact 70 ,Trilogysuccessful formulations are Garlic Pallet, Allamonda Pellet, Triact 70 ,Trilogy
70, Dematode, demite, Descide, etc.70, Dematode, demite, Descide, etc.
 Garlic andGarlic and Allam andaAllam anda tablet have been proved effective in plant diseasetablet have been proved effective in plant disease
control, specially for seed borne diseases.control, specially for seed borne diseases.
 Botanical pesticides fit into IPM and organic farming.Botanical pesticides fit into IPM and organic farming.
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