The Effect of Pesticides on the Yield and Botanical Composition of a Newly‐sown Ryegrass Ley and of an Old Mixed Pasture

Newly‐sown S24 perennial ryegrass at Hurley and old established ryegrass‐dominant mixed pasture at Rothamsted were treated with several pesticides, singly and in combination, over the period 1969–73. Yields were either unaffected or increased by up to 30% in any one year, depending on the treatment, the newly‐sown sward giving the more consistent response from year to year.