This is the second survey of pesticide usage practices conducted in the arable sector in Northern Ireland, providing comparative data to that obtained in the previous survey in 1990 (Jess et al ., 1992). Information on all aspects of pesticide usage was collected from 327 holdings throughout the Province representing 15% of the total area of arable crops grown. Quantitative data has been adjusted to provide estimates of total pesticide usage. While the area of arable crops grown in Northern Ireland between 1990 and 1992 declined by 5%, particularly in Counties Antrim and Tyrone, to 58,000 hectares the pesticide-treated area of arable crops increased by 4% to 245,485 spray hectares. The most notable increase in area treated (27%) was in the use of insecticides in spring and winter wheat crops and winter oat crops in Counties Armagh and Down. The use of growth regulators also increased, by 22%, particularly in spring wheat and oats in Counties Antrim and Armagh. Conversely, the total quantity of pesticide used decreased by 10%, reflecting the use of herbicides and growth regulators at lower dosage rates than recorded previously.

Overall, regional pesticide usage approximated to the areas of arable crops grown in each county. Pesticides were applied to 99% of the total area of arable crops grown in Northern Ireland in 1992, with a mean of four applications. Fungicides were applied to 43% of the pesticide-treated area accounting for 31% of the total quantity of pesticide used. Potatoes, including seed, early and maincrop, received 82% of fungicide active ingredients representing 64% of the area of arable crops treated with fungicides. The most extensively used fungicide active ingredient was mancozeb to control potato blight ( Phytophthora infestans ) in potatoes.

Herbicides and desiccants were applied to 31% of the pesticide-treated area, accounting for 65% of the total quantity of pesticide used. Sulphuric acid, used as a potato haulm desiccant, accounted for 74% of the weight of herbicide and desiccant active ingredients applied but only 1.6% of the area treated by this pesticide group. Barley crops received 14% of the total weight of herbicide and desiccant active ingredients, representing 54% of the area treated by this pesticide group. The most commonly used herbicide and desiccant active ingredient, used for general weed control, was metsulfuron-methyl.

Seed treatments accounted for 18% of the total pesticide-treated area. Approval for the use of seed treatments containing phenylmercury acetate was revoked on 31 st March 1992. However the majority of seed for sowing in 1992 had been acquired before this date and therefore phenylmercury acetate continued to be the most extensively used cereal seed treatment.

Growth regulators, primarily applied to winter cereals, accounted for 4.3% of the total pesticide-treated area and 3% of the total weight of pesticides applied. The most commonly recorded growth regulator active ingredient was chlormequat, accounting for 50% of growth regulator-treated area.

Insecticides and molluscicides were applied to 2.8% of the pesticide-treated area accounting for 0.3% of the total quantity of pesticides used. The most commonly used insecticides were cypermethrin on winter wheat and oxydemeton-methyl on spring barley to control aphids. Metaldehyde was used on 95% of the molluscicide-treated area of oilseed rape crops.

A total of 179 products, comprising 111 active ingredients, were recorded used on field crops in the survey.

In addition to information concerning field applications of pesticides to crops, data were collected relating to post-harvest/storage treatments applied to farm stored potatoes. It was estimated that 191,019 tonnes of potatoes were stored, on-farm, following the 1992 growing season. Ware potatoes accounted for 73% of the total tonnage of stored potatoes, seed potatoes 18% and mixed seed and ware storage 9%. An estimated 3,050 kilograms of pesticides were applied to 23,825 tonnes of stored potatoes. Tecnazene, as a single active ingredient or in formulation with either nonylphenoxypoly (ethylenoxy) ethanol-iodine complex or thiabendazole, was the most extensively used pesticide accounting for 94% of the total weight of pesticides applied to 85% of treated stored potatoes. The formulation of tecnazene/nonylphenoxypoly (ethylenoxy) ethanol-iodine complex accounted for 62% of the total quantity of pesticides applied to 56% of treated stored potatoes.

A full list of published reports is available together with abstracts from other relevant published work.

For further information on this work please contact:

Pesticide Usage Survey Group
Agri-food and Biosciences Institute
Newforge Lane
Belfast BT9 5PX

Email: pesticide.science@afbini.gov.uk
Tel: +44 (0)28 90 255689
Fax: +44 (0)28 90 255035