EFFICIENCYEFFICIENCY OF SOME LOCAL OF SOME LOCAL PLANTS ESSENTIAL OIL AGAINST PLANTS ESSENTIAL OIL AGAINST

SEED-BORNE AND SEED SEED-BORNE AND SEED TRANSMITED FUNGI OF RICETRANSMITED FUNGI OF RICE

KABORE K.BKABORE K.B11..  ; KOÏTA E ; KOÏTA E11. ; OUEDRAOGO I. ; OUEDRAOGO I11.. et NEBIE Ret NEBIE R22..

(1) (1) Institut de l’Environnement et de Recherches Agricoles Institut de l’Environnement et de Recherches Agricoles (INERA)(INERA)((22) Institut de Recherche en Sciences Appliquées et Technologies ; ) Institut de Recherche en Sciences Appliquées et Technologies ;

Département Substances Naturelles Département Substances Naturelles (IRSAT)(IRSAT) Burkina FasoBurkina Faso

HEADLINESHEADLINES

• IntroductionIntroduction

• ObjectivesObjectives

• Materials and MethodsMaterials and Methods

• ResultsResults

• DiscussionDiscussion

• Conclusions and PerspectivesConclusions and Perspectives

• AknowledgementAknowledgement

INTRODUCTIONINTRODUCTION• Importance of rice as food cropImportance of rice as food crop• Biotic Constraints to productionBiotic Constraints to production

– Seed-borne fungi as major mean of rice diseases Seed-borne fungi as major mean of rice diseases transmission and dissemination.transmission and dissemination.

• Increasing dependance of rice roduction upon the Increasing dependance of rice roduction upon the use of conventionnal pesticides.use of conventionnal pesticides.– Negative impact on Environment and healthNegative impact on Environment and health

• Need in research of alternate biopesticides Need in research of alternate biopesticides – Research Hypotheses : Some traditionnal local plant Research Hypotheses : Some traditionnal local plant

species used as medical substances could have species used as medical substances could have fungicide properties (fungicide properties (Kaboré etKaboré et al., al.,2002)2002)

OBJECTIVESOBJECTIVES

• OVERALL OBJECTIVEOVERALL OBJECTIVE– Identify local plant species with bio pesticides Identify local plant species with bio pesticides

properties that can be used in agriculture.properties that can be used in agriculture.

• SPECIFIC OBJECTIVESSPECIFIC OBJECTIVES– Identify local plant species with essential oil Identify local plant species with essential oil

presenting fongicide properties;presenting fongicide properties;– Determine efficient level of application of essential Determine efficient level of application of essential

oil for rice seed treatment against fungal mycoflor.oil for rice seed treatment against fungal mycoflor.

MATERIAL AND METHODS (contd)MATERIAL AND METHODS (contd)

• local plants species used for studylocal plants species used for study:: – Cymbopogon citratusCymbopogon citratus (D.C.) Stapf. (D.C.) Stapf. Common Common

french name : citronnelle (french name : citronnelle (Poaceae );Poaceae );

– Cymbopogon giganteus Cymbopogon giganteus ChiovChiov ( ( Poaceae );Poaceae );

– Lippia multifloraLippia multiflora Moldenke Moldenke, (, (Verbenaceae)Verbenaceae) Common french name : thé de Gambie ;Common french name : thé de Gambie ;

– Ocimum basilicumOcimum basilicum L L, (, (Lamiaceae)Lamiaceae). .

MATERIAL AND METHODESMATERIAL AND METHODES

• Rice variety used : IR6623275-5-12 Rice variety used : IR6623275-5-12 • Seed-borne fungi and their contamination Seed-borne fungi and their contamination

level (%) :level (%) :– BipolarisBipolaris oryzaeoryzae = = 28,528,5– CurvulariaCurvularia oryzaeoryzae = = 11,511,5– CurvulariaCurvularia lunatalunata = = 13,513,5– FusariumFusarium moniliformemoniliforme = 48,5 = 48,5– PhomaPhoma sorghinasorghina = 19,5 = 19,5

Cymbopogon citratus

MATERIAL AND METHODS (contd)MATERIAL AND METHODS (contd)

• Essential oil was extracted by hydrodistillation Essential oil was extracted by hydrodistillation with a Clevenger apparatus from fresh leaves with a Clevenger apparatus from fresh leaves collected from the different species during rainy collected from the different species during rainy season 2004.season 2004.

• Essential oil of Essential oil of Ocimum basilicumOcimum basilicum L., L., Cymbopogon citratusCymbopogon citratus (DC) Stapf (DC) Stapf, , Cymbopogon Cymbopogon giganteusgiganteus Chiov Chiov.. etet Lippia multiflora Lippia multiflora Moldenke Moldenke was used at the concentration of 1% ; 1,5% et 2% was used at the concentration of 1% ; 1,5% et 2% corresponding respectively to 10 ml, 15 ml et 20 corresponding respectively to 10 ml, 15 ml et 20 ml per litre of media ( PDA) ml per litre of media ( PDA)

MATERIAL AND METHODSMATERIAL AND METHODS (contd)(contd)

• The conventionnal control for cereal seed treatment The conventionnal control for cereal seed treatment fungicide was fungicide was Calthio DSCalthio DS ( 20 % of Lindane and ( 20 % of Lindane and 25 % of Thiram.25 % of Thiram. This product was incorporated This product was incorporated into the media (2,5 g per litre of PDA media)into the media (2,5 g per litre of PDA media)

• Seed treatment Seed treatment

– Seed health testing by the blotter method Seed health testing by the blotter method

– Four replicates of 50 seed (25 seeds per Petri dish) Four replicates of 50 seed (25 seeds per Petri dish) were soaked for 20 to 24 hours in essential oil were soaked for 20 to 24 hours in essential oil emulsion (1%, 1,5% and 2%) ;emulsion (1%, 1,5% and 2%) ;

– Incubation à 22°CIncubation à 22°C

MATERIAL AND METHODS (contd)MATERIAL AND METHODS (contd)

• • Radial growth measurement of the fungiRadial growth measurement of the fungi– Essential oils were incorporated into the PDA Essential oils were incorporated into the PDA

media at the concentration of media at the concentration of 1%, 1,5% and 2%.1%, 1,5% and 2%.– Petri disheswere Petri disheswere incubated at 28°C under incubated at 28°C under

alternate cycles of 12h of NUV light and 12h alternate cycles of 12h of NUV light and 12h of darkness.of darkness.

– Measurement of Measurement of radial growth (cm) after 3, 5 , radial growth (cm) after 3, 5 , 7 and 10 days of incubation (perpendicular 7 and 10 days of incubation (perpendicular diametre Method).diametre Method).

– Experimental design : Split plot with oils as Experimental design : Split plot with oils as main factor and concentrations as secondary main factor and concentrations as secondary factor.factor.

MATERIAL AND METHODS (contd)MATERIAL AND METHODS (contd)

– Efficiency of extracts (Greche et Hajjaji, 2000) : Efficiency of extracts (Greche et Hajjaji, 2000) :

E(%) = 100[DMT-DMH]/ DMTE(%) = 100[DMT-DMH]/ DMT

where DMT represents the mean diametre of the where DMT represents the mean diametre of the control (non treated) and DMH the mean control (non treated) and DMH the mean diametre of the treatment with essential oil.diametre of the treatment with essential oil.

– Data were analysed for ANOVA with Data were analysed for ANOVA with STATVIEW/SAS software and the means were STATVIEW/SAS software and the means were separated by the Student- Newman- Keuls test separated by the Student- Newman- Keuls test

RESULTSRESULTS

ANOVAANOVA

• ANOVA indicated significant différencies ANOVA indicated significant différencies between the traetments for the test of radial between the traetments for the test of radial growth of the fungi as well as the test of seed growth of the fungi as well as the test of seed germination ;germination ;

• No significant difference was observed No significant difference was observed between the tested concentrationsbetween the tested concentrations

Efficiency of essential oilsEfficiency of essential oils

• All the four tested essential oils inhibited the All the four tested essential oils inhibited the radial growth of the fungi : radial growth of the fungi : Bipolaris oryzae, Bipolaris oryzae, Curvularia lunata Fusarium moniliforme Curvularia lunata Fusarium moniliforme andand Phoma sorghina.Phoma sorghina.

• When considering the different concentrations, When considering the different concentrations, these oils reduced significantly the incidence of these oils reduced significantly the incidence of the four seed-borne fungal species as compared the four seed-borne fungal species as compared to the controls.to the controls.

a b c d e

Pétri dishes presenting efficiency of Pétri dishes presenting efficiency of C. CitratusC. Citratus essential oil against essential oil against Curvularia lunataCurvularia lunata (a=concentration 1%, b=concentration 1,5 %,  (a=concentration 1%, b=concentration 1,5 %, c=concentration 2 %, d=non treated control , e= control calthio).c=concentration 2 %, d=non treated control , e= control calthio).

EFFICIENCY OF ESSENTIAL OIL AGAINST

RADIAL GROWTH OF Bipolaris oryzae

0

20

40

60

80

100

120

Citronnelle

Lippia

Giganteus

Ocimum

Tabs

Tcalthio

Eff

icie

ncy

leve

l (%

)

03.123 2

29.938

8.625

05

101520253035

See

d co

ntam

inat

ion

leve

l (%

)

Global seed contamination following treatment with essential oil

0

510

15

2025

30

3540

45

C. citratus C.giganteus

L.multiflora

Control To T calthio

See

d co

ntam

inat

ion

leve

l (%

)

Bo Cl Fm PsIncidence of Seed –borne fungi after seed treatment with essential Incidence of Seed –borne fungi after seed treatment with essential

oiloil (B. (B. oryzae, C. lunata, F. moniliforme oryzae, C. lunata, F. moniliforme et et P. sorghinaP. sorghina

DISCUSSIONDISCUSSION• Essential oil of Essential oil of C. citratus, C. giganteus, L. C. citratus, C. giganteus, L.

multiflora multiflora andand O. basilicum O. basilicum reduced significantly reduced significantly the incidence of seed contamination by the fungi the incidence of seed contamination by the fungi and inhibited the radial growth of fungal colonies and inhibited the radial growth of fungal colonies as compared to the different controls. as compared to the different controls.

• The presence of The presence of citralcitral in the essential oil of in the essential oil of C. C. citratuscitratus (Djibo., 2000)(Djibo., 2000), and also the presence of , and also the presence of oxygenous components like oxygenous components like linalollinalol and and eugénoleugénol in in essential oil of essential oil of O. basilicumO. basilicum (Nébié (Nébié et alet al., 2002)., 2002) could explain antifungic properties of these two could explain antifungic properties of these two plant speciesplant species..

DISCUSSION (Contd)DISCUSSION (Contd)• These results are comparable to those of These results are comparable to those of Dongma Dongma

(2002)(2002) who evaluated in vito the antifungic who evaluated in vito the antifungic activity of essential oil of activity of essential oil of Citrus limonCitrus limon and and Citrus Citrus latifolialatifolia against the inciting fungus of citrus against the inciting fungus of citrus phaeoramulariosis  (phaeoramulariosis  (Phaeoramularia angolensisPhaeoramularia angolensis).).

• Concerning the seed germination test by the blotter Concerning the seed germination test by the blotter method, essential oils of method, essential oils of C. citratusC. citratus and and C. C. giganteusgiganteus were highly efficient against the fungi were highly efficient against the fungi but were slightly phytotoxic. but were slightly phytotoxic. Dabiret (2004)Dabiret (2004) came came to the same conclusion that essential of the genus to the same conclusion that essential of the genus Cymbopogon Cymbopogon has a negative effect on seed has a negative effect on seed germination.germination.

CONCLUSIONSCONCLUSIONS

• Essential oils ofEssential oils of C. citratus, C. giganteus, L. C. citratus, C. giganteus, L. multiflora multiflora andand O. basilicum O. basilicum have antifongic have antifongic propertiesproperties.

• For the firts time, efficency of L. multiflora oil in improving the germination capacity of rice seed under laboratory conditions was demonstrated.

• Essential oil of Lippia did not exhibited any phytotoxic effect at the tested concentrations as compared to oils of Cymbopogon, and Ocimum; moreover; it reduced by up to 28,81 % the incidence of seed-borne and seed-transmitted fungi.

PERSPECTIVESPERSPECTIVES

• The tested concentrations of some The tested concentrations of some essential oils used in this study should be essential oils used in this study should be lowered because of the observed lowered because of the observed phytotoxicity they produced on the seed phytotoxicity they produced on the seed germination tested by the blotter method.. germination tested by the blotter method..

AKNOWLEDGEMENTAKNOWLEDGEMENTWe like to thank We like to thank Adama OUATTARA and Adama OUATTARA and

Raphaël SANOU for their technical contribution Raphaël SANOU for their technical contribution

to the realization of the present work .to the realization of the present work .