Transcript C11_Contans

FOOD QUALITY AND SAFETY
France
MODULE C11
© ENDURE, February 2007
Biological control:
the case study of Coniothyrium minitans
in France
Background: sclerotinia
nuisibility
FOOD QUALITY AND SAFETY
A common disease occuring
intermittently on oil-seed
rape
– severe epidemics occur only
one or twice a decade (2000
et 2006)
– sometimes no or very poor
epidemics (2003)
% infected fields
(sclerotinia stem rot > 10%)
60
50
40
30
20
10
0
2000
2001
2002
2003
2004
2005
2006
Stem rot of 0 to 10 %
Yield losses < 0.2 T/ha
No control
0
Stem rot of 10 to 100 %
Yield losses > 0.2 T/ha
(0.1 T/ha per 10% of stem rot
10
100
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but a damaging disease with
a damage threshold of 10 %
of sclerotinia stem rot
Sclerotinia
Life cycle
FOOD QUALITY AND SAFETY
Apothecia
Sclerotia in soil
Fall of petals
Sclerotia on stems
Infected petals on leaves
Favorable
climate
Stem rot
Infected leaves
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Favorable
climate
Disease management
FOOD QUALITY AND SAFETY
Chemical control was usually based on
protective and systematic spray at early
bloom with cheap fungicides
 Numerous useless sprays
 Development of fungicides resistance, eg carbendazim (in
France)
But the context is requiring
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 To reduce the use of fungicides according to their negative
environmental effects
 To reduce expensive inputs
 To justify the use of pesticides according to European
regulation
IPM solutions
on Sclerotinia
BIOFONGICIDE
FOOD QUALITY AND SAFETY
(rotation and field situation)
Risk grid
(field and climate)
Apothecia
Sclerotia in soil
Fall of petals
Climatic
modelling
Sclerotia on stems
Infected petals on leaves
Favorable
climate
Stem rot
Infected leaves
FONGICIDE
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Favorable
climate
Sclerotinina Resistance
on fungicides
FOOD QUALITY AND SAFETY
Efficiency of fungicide against Sclerotinia
(french network)
Nb trials
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Damages
Coniothyrium minitans:
an agent of biological control
FOOD QUALITY AND SAFETY
The contact between spores of Coniothyrium and
sclerotia are stimulating the germination of spores. C.
minitans develops a mycelium that can contaminate the
sclerotia
Infection of sclerotia
Arsenal enzyme => destruction of hyphal cell of the
sclerotia
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Sclerotia becomes flabby and unable to germinate and
form apothecia
Coniothyrium minitans:
an agent of biological control
FOOD QUALITY AND SAFETY
Contans ® WG is not used as a chemical
fungicide:
– To be effective, Contans ® WG should be put in direct
contact with the sclerotia
 by spraying and incorporation (sensitive to UV) before
planting of rapeseed
 By spraying on infected crop residues
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The life of Contans ® WG is approximately 12
months, it should repeat the treatment every
year to bring the medium term to reduce the
infectivity of the soil.
Recommandations
FOOD QUALITY AND SAFETY
Contans WG ® : commercial product with
Coniothyrium minitans spores
– Before the seedling of oil-seed rape:
 At the rate of 2 kg / ha.
 This practice ensures the destruction of sclerotia surface that
reduces the pressure of inoculum (less ascospores to contaminate
the flowers of rapeseed) and limit stem attacks of rape.
– On infected crop residues:
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 At the rate of 1 to 2 kg / ha.
 Infection of sclerotia by C.minitans helps to reduce the stock of
sclerotia in the soil and, consequently, to prevent parasitic pressure
later.
Conclusion: Response to
general principles of IPM
FOOD QUALITY AND SAFETY
Environment:
– Reduced quantities of pesticides: general principle 6
– Non chemical measures: general principle 4
Agronomy:
Monitoring and DSS : general principle 2
Prophylaxis : general principle 1
Choice of products : general principle 5
Resistance management: : general principle 7
Limitation of dose: general principle 6
Level thresholds : general principle 3
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