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

The effect of barley-legume intercrop in an organic farming system on disease incidence was investigated. The legumeswere 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. Netblotch (Pyrenophora teres), brown rust (Puccinia recondita) and powdery mildew (Blumeria graminis f.sp. hordei) (inorder of incidence) were monitored on barley between flag leaf emergence and heading. The levels of all three diseaseswere reduced in every intercrop treatment compared to the barley monocrop. However, this reduction was only statisticallysignificant in the pea treatments for net blotch.