PREHARVEST ASSESSMENTS OF ELYMUS-REPENS (L) GOULD INTERFERENCE IN 5 ARABLE CROPS

Relationships between yield of live arable crops and increasing Elymus repens infestations assessed near before harvest are presented from f ield trials conducted on the same location through four years. In peas , spring barley and spring oilseed rape, yield responses to E. repens interference were closely related to E. repens shoot biomass pre-harve st. Also the number of E. repens spikes pre-harvest was related to cro p yield, although the correlations were not as high, In winter wheat a nd winter rye, the correlations, with both shoot biomass and spike num ber, were smaller than in the spring-sown crops, but still significant , In all crops, the relationships interacted with years but the intera ctions were not statistically significant in many cases. Mechanical co ntrol in the stubble and pre- or post-harvest application of glyphosat e are common control measures against E. repens, and pre-harvest asses sments of E, repens infestations show promise for judging the seriousn ess of a current E. repens problem before making control decisions.