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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![is most promising, and hand applicators are now widely used. Granule applicators for tractor mounting are also available and these, together with the other methods, were used in trials with 17 possible alternative chemicals—mostly organophosphorus insecticides—in 1965 and 1966. The trials were done on cauliflowers, cabbages, turnips, and swedes. Chlorfenvinphos gave the best results as granules applied round the transplants, and compared very favourably with aldrin and dieldrin. Application as a band of granules before planting (“‘bow-wave’ technique) gave variable results, but satisfactory results were obtained when the granules were applied as a band over the plants just before the fly oviposition peak. Chlorfenvinphos also gave good control when applied as a liquid drench to cauliflowers and cabbages in the field. But this material was not completely satisfactory as a root dip for cabbages and cauliflowers, and some phytotoxicity was seen; because it lacks persistence as a dip it usually needs to be followed-up with a drench treatment. Chlorfenvinphos seed dressings gave promising results with swedes in the northern counties. Diazinon was almost as good as chlorfenvinphos when applied as a drench under some conditions, though it also lacks persistence, and while often satisfactory on _ cauliflowers and cabbages it was unsatisfactory on swedes. Of the other materials tested, the best were thionazin, N—2790, and trichloronate, which gave results equal to chlorfenvinphos and diazinon in some trials. All three gave consistently good results on cauliflowers and turnips. Inconsistent results were obtained with mecarbam, azinphos-methy]l, parathion and trichlorphon and disulfoton. Phorate was generally not effective. Bromophos, ethion, fenitrothion and fenchlorphos were also tested. Ethion and fenitrothion did not show much promise. Bromophos was liable to cause severe phytotoxicity, and no significant control of cabbage root fly was obtained with fenchlorphos. It will have been noticed, in Tables 2.2.1, 2.2.2, and 2.2.3, that about 12,000 acres (5,000 ha) of edible brassicae were treated with organophosphorus alternatives in 1966. Nearly half this acreage was treated with diazinon, about 2,000 acres (800 ha) received chlorfenvinphos, and a slightly larger acreage was treated with phorate. These treat- ments were, according to the growers, applied against cabbage root fly, and suggest that there is a trend away from the organochlorine insecticides for controlling this pest. This can be partly explained by increasing dieldrin resistance. 2.3. Roots for Human Consumption Although normally considered a ‘vegetable’, first-early potatoes have been con- sidered along with second-early and maincrop varieties at section 1.6. The present section covers carrots, parsnips and celery, turnips and swedes, beetroot, and radishes. About 53,000 acres (21,000 ha) of these crops were grown in 1966, half the acreage being in carrots. 2.3.1. Carrots, Parsnips and Celery. Considered together because they are all liable to be damaged by carrot fly. Nearly 27,000 acres (11,000 ha) of carrots were grown in 1966, less than 2,000 acres (800 ha) being early varieties. The 1966 VS data are shown for the three crops in Table 2.3.1. Some correspondents consider the dieldrin data in Table 2.3.1 to be an under- estimate. 2.3.1. The Need for these Treatments. Carrot Fly is widely distributed, and there is now evidence of dieldrin resistance in at least three localities in the eastern counties (Wright and Coaker, 1968). Aldrin and dieldrin were, nevertheless, used on about 13 per cent of the carrot acreage in 1966, with about one-eighth of the acreage being grown from dieldrin-dressed seed. These materials were also used on about a quarter of the celery acreage, and to a small extent on parsnips. In all three crops there is a trend to organophosphorus alternatives: about 5,300 acres (2,100 ha) of carrots were](https://iiif.wellcomecollection.org/image/b32173076_0121.jp2/full/800%2C/0/default.jpg)
