Effect of barley-legume intercrop on disease frequency in an organic farming system

Summary

The effect of barley-legume intercrop in an organic farming system on disease incidence was investigated. The legumes were lupin, faba bean and pea. Diseases were detected on pea and barley. On pea, only ascochyta blight (Ascochyta pisi) was observed. When either pea variety was intercropped with barley, the level of ascochyta blight was reduced. Net blotch (Pyrenophora teres), brown rust (Puccinia recondita) and powdery mildew (Blumeria graminis f. sp. hordei) (in order of incidence) were monitored on barley between flag leaf emergence and heading. The levels of all three diseases were reduced in every intercrop treatment compared to the barley monocrop. However, this reduction was only statistically significant in the pea treatments for net blotch.