here - First Legume Society Conference (LSC1)

Book of Abstracts First Legume Society Conference 2013: A Legume Odyssey Novi Sad, Serbia, 9-11 May 2013
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Reducing biotic stresses in legumes through intercropping with durum wheat
Laurent Bedoussac 1,2 , Etienne-Pascal Journet 2,3 , Eric Justes 2,4
1 ENFA, Castanet-Tolosan, France
2 INRA, UMR1248 AGIR, Castanet-Tolosan, France
3 CNRS, UMR2594 LIPM, Castanet-Tolosan, France
4 Université Toulouse, INPT, UMR AGIR, Toulouse, France
Intercropping - growing simultaneously two or more species in a same field - is known as an
agricultural practice which can improve yield compared to sole cropping. However its efficiency
in significantly reducing biotic factors has been controversial while they can strongly affect both
yield and grain quality in low input systems. The aim of our study was to evaluate the assumption
that intercropping legumes with durum wheat can reduce legume pests (green aphids, pea leaf
weevils and pea broad bean beetles), weeds and diseases (legume ascochyta and rust, wheat
mildew and brown rust). Field experiments have been carried out in SW France since 2006.
Durum wheat, winter pea and faba bean were evaluated as sole crop (SC) and intercrop (IC) with
or whithout fertiliser-N supply or chemical pest management. Our results further document the
contrasting effects of IC against various pests due to interactions between plant architecture,
disease dispersion, insect behaviour and farming practices: i) weeds were always reduced in IC
compared to legume SC but not compared to wheat SC, ii) pea aphids were significantly reduced
in IC while weevils were not or slightly affected, iii) diseases were mostly reduced in IC or at the
same level as in SC and rarely increased. Durum wheat-winter pea intercropping thus seems
efficient in reducing some diseases and pests through environmental modifications (resources
dilution, physical barrier, microclimate shift) resulting from the association of complementary
functional groups of species. IC could therefore be a way to reduce the use of pesticides.
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