This is the third survey of pesticide usage on vegetable crops produced for human consumption in Northern Ireland, providing comparative data to that obtained in the previous surveys in 1991, (Jess et al., 1993) and 1995 (Kidd et al., 1998). Information on all aspects of pesticide usage was collected from 93 holdings throughout the province, representing 52% of the total number of growers and 83% of the total area of vegetable crops grown. Quantitative data has been adjusted to provide estimates of total pesticide usage, which in 1999 was 1528 hectares; a 15% increase compared with 1995.

By comparison with 1995, the area of vegetable crops grown in Northern Ireland increased by 15% to 1528 hectares. The pesticide-treated area increased by 39% to 10,460 spray hectares, while the quantity of pesticide active ingredients (a.i.s) applied was virtually unchanged at approximately 7 tonnes. The fungicide-treated area increased by 125% (mainly due to an increase in the number of spray applications) while the quantity of fungicide active ingredients applied decreased by 5%. The area of herbicide and desiccants application increased by 46%, while the weight of active ingredients applied increased by 26%. The area treated with insecticides increased by 19% but the quantity used of active ingredients decreased in by 45%. This was principally due to the reduction in use of organophosphates and a related increase in the use of pyrethroids. The area treated with organophosphates decreased from that recorded in 1995 by 68%, while the data showed approximately a four-fold increase in the use of pyrethroid insecticides during the same period. There was a five-fold increase in the molluscicide-treated area compared with previous years. The area of vegetable crops sown or planted with treated seed decreased by 23% in the four-year period 1995 to 1999 while the weight of active ingredients used decreased by 89%. Soil fumigants, applied to four hectares of vegetable production land in 1991, were not recorded in use in 1999. Repellents, applied to 50 hectares, were recorded for the first time in 1999.

Pesticides were applied to the total area of vegetable crops grown in Northern Ireland in 1999, with a mean of two applications. Fungicide applications represented 20% of the pesticide-treated area and 17% of the total quantity of pesticide used. Herbicides and desiccants accounted for 36% of the pesticide-treated area and 65% of the total quantity of pesticide used. Insecticides, applied to 36% of the pesticide-treated area, accounted for 15% of the total quantity of pesticide used. Seed treatments applied to vegetable crops grown in 1999 accounted for 6% of the pesticide-treated area, representing less than 1% of the quantity of active ingredients applied. Molluscicides accounted for 2% of the total pesticide-treated area and less than 1% of the quantity of pesticide applied to vegetable crops grown in Northern Ireland in 1999.

Brassica crops received 34% of the total weight of fungicides applied, representing 53% of the area of vegetable crops treated with fungicides. The single most commonly used fungicide active ingredient applied to brassicas was difenoconazole. Carrots and parsnips collectively accounted for 39% of the quantity of fungicide active ingredients applied, representing 28% of the fungicide-treated area, with the single active ingredient tebuconazole being most frequently used on these vegetable crops. Linuron was the herbicide/desiccant active ingredient most commonly applied to vegetable crops, particularly carrots and parsnips. However, trifluralin was also frequently used, mainly on brassicas.

Together, carrots and parsnips accounted for 47% of the insecticide-treated area, representing 48% of the quantity of insecticide active ingredients applied. Brassicas accounted for 44% and 25% of the insecticide-treated area and quantity applied, respectively. Pyrethroids were the most frequently used insecticide active ingredients, with lambda-cyhalothrin being the most commonly used insecticide. A total of 104 products, including one registered biological control agent and five nutrient feeds, were recorded in use on vegetable crops in this survey.

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