The effect of controlling Alopecurus myosuroides Huds. and Avena fatua L. individually and together, in mixed infestations on the yield of wheat

Summary: Mixed infestations of Alopecurus myosuroides and Arena fatua growing in wheat were controlled individually or together in three experiments. Difenzoquat and ciofop‐isohutyl were applied at the early tillering or early stem extension stages of the crops. Early control of both species resulted in significantly higher yields than later control, even though weed emergence was incomplete at the early applications. Herbicides, re‐applied at the second date, improved the control of wild‐oats hut not of black‐grass; yields were not enhanced by this second application Halving the dose of herbicide gave little reduction in weed control or crop yield at the early date, but there was a greater response to dose with the later application. Yields were lower where only one weed was controlled. This work shows the need for broad spectrum control early in the life of the crop to safeguard yield where black‐grass, and wild oats occur together in large numbers.