After earlier trials of herbicides in raspberry cane nurseries from 1955 to 1958, a three-year trial of monuron (at rates of 1.0, 2 and 3.0 lb. per acre of simazine (1.0, 2.0 and 3.0 lb.) and of a mixture of 2,4-DES (3.6 lb.) with propham (5.0 lb.) was conducted in a nursery planted with the variety Malling Exploit in 1958. The treatments were applied annually in late winter or spring. Hand cultivation for weed control was unneccessary on the 2.0 lb. and 3.0 lb. simazine plots and scarcely needed on the 3.0 lb. monuron plots, but the 1.0 lb. simazine, 1.0 lb. and 2.0 lb. monuron and 2,4-DES/propham treatments were less effective. The plots on which chemical weed control was effective were superior to the others in the numbers and quality of the canes which they produced. Seed germination tests on soil samples taken twelve months after the final applications of the herbicides revealed much smaller numbers of weed seeds in the topmost 2 in. zone of soil under the successful treatments than under those which were less successful.
On the basis of this trial and collateral experience, simazine at 2.0-3.0 lb. per acre is considered to be an effective and satisfactorily safe herbicide treatment for raspberry cane nurseries; but there may be value in the occasional use of alternative materials to prevent the build-up of resistant weed species.