Further review of certain persistent organochlorine pesticides used in Great Britain.
- Great Britain. Advisory Committee on Pesticides and Other Toxic Chemicals
- Date:
- 1969
Licence: Public Domain Mark
Credit: Further review of certain persistent organochlorine pesticides used in Great Britain. Source: Wellcome Collection.
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![Table 1.1.1. Treatments Applied to Wheat, Autumn 1965—Spring 1966 Acreages* Materials Believed Treated Wheat Bulb Fly Seed Dressings Containing Aldrin or Dieldrin ; f ‘ [ 97,000 Containing 40 per cent gamma—BHC ; , : 181,000 Wireworm Seed Dressings Containing 20 per cent—25 per cent gamma-BHC .| 1,147,000 Field Treatments Aldrin : 4 : : ; : : : (6,700) Organophosphorus Wheat Bulb Fly Sprays d : 36,500 Acreage Grown: ; . ' : : : .| 2,171,400 * (1,000 acres=405 hectares) The 1962-64 estimates indicated that about 290,000 acres (117,000 ha) of wheat were sown with seed dressed against wheat bulb fly. The 1966 data suggest that about 247,000 acres (100,000 ha) were sown with similarly protected seed in the autumn of 1965. The earlier data also indicated that about 30,000 (12,000 ha) of wheat were given field treatments against the fly, compared with about 43,000 (17,000 ha) in 1966. 1.1.1.1. The Need for these Treatments. It has been estimated (Potter, Strickland and Bardner, 1965) that 230,000-240,000 acres (93,000—-97,000 ha) of wheat are normally grown under conditions which might attract a damaging level of wheat bulb fly attack in a year when the fly is unusually abundant. In such a year crop protection chemicals probably save the production equivalent of 84,000 acres (34,000 ha) of wheat worth about £3-3 million. Wheat bulb fly egg counts, which are done routinely by Advisory Service specialists each autumn in the areas where the pest is troublesome, were higher than usual in 1965: ‘very heavy’ in parts of Yorkshire; ‘the highest ever recorded’ in the eastern counties, and also in the east Midlands. There can be little doubt that the treatments applied in 1965-66 were justified. 1.1.1.2. Alternative Chemicals for Wheat Bulb Fly Control. The chemical control of wheat bulb fly has been critically examined by the Wheat Bulb Fly Panel consisting of members from the specialist branch of the Advisory Service and from Research Stations. The Panel reports as follows :— Seed Dressings are relatively cheap (often less than 10/— per cwt [£1 per 100 kg] of - treated seed), control is obtained with the minimum of insecticide, and there is some selectivity in that the materials are only applied where needed. Many field trials over the past few years indicate that there is little to choose between dieldrin, chlorfenvinphos and ethion, all of which have performed well on a wide range of soil types. Chlorfen- vinphos, as a dry seed dressing, caused some delay in early plant growth but this did not affect final grain yield; control on some light, freely draining, soils was not good. Ethion did not affect plant growth. Both materials prevented some larval entry and killed some of the larvae that had succeeded in entering the plants. Diazinon gave some control on peat soils but was not effective on mineral soils, while carbophenothion was very promising but needs further field testing. None of these organophosphorus materials is yet available in approved commercial formulations. Gamma-BHC (lindane) has continued to be less useful than dieldrin, particularly on peat soils.](https://iiif.wellcomecollection.org/image/b32173076_0104.jp2/full/800%2C/0/default.jpg)
