ERODIUM-CICUTARIUM DENSITY AND DURATION OF INTERFERENCE EFFECTS ON YIELD OF WHEAT, OILSEED RAPE, PEA AND DRY BEAN

Field studies were conducted to determine the effect of various densit ies and duration of interference of Erodium cicutarium (L.) L'Her. ex Ait. on the yield of wheat, oilseed rape, pea and dry bean. The magnit ude of yield reductions caused by E. cicutarium differed among the cro ps. Results indicate that the ranking of crop tolerance to E. cicutari um, when established at their recommended planting densities, was whea t > oilseed rape > pea similar or equal to dry bean. Maximum yield red uction occurred at E. cicutarium densities of 100-200 plants m(-2) and were 36% for wheat, 37% for oilseed rape, 82% for dry bean and 92% fo r pea. Crop yield progressively decreased as the duration of E. cicuta rium interference increased. Three weeks of E. cicutarium interference after emergence was sufficient to reduce the yield of all crops, indi cating the importance of controlling this weed early in the growing se ason. The mean yield reduction for each week of E. cicutarium interfer ence was 1.6%, 2.7%, 3.6% and 6.3% for wheat, oilseed rape, pea and dr y bean respectively. E. cicutarium is therefore a weed that warrants c onsideration for control in annual cropping systems.