Pesticide usage report: Arable crops 2006

Summary

This is the ninth survey of pesticide usage practices on arable crops in Northern Ireland, providing comparative data to that obtained in the previous surveys in  1990, (Jess et al., 1992), 1992 (Jess et al., 1995), 1994 (Jess et al., 1997), 1996 (Jess et al., 2000), 1998 (Jess et al., 2002), 2000 (Withers et al., 2004), 2002 (Withers et al., 2004) and 2004 (Withers et al., 2006).

Information on all aspects of pesticide usage was collected from 273 holdings throughout the Province, representing 27% of the total area of arable crops grown. Quantitative data has been adjusted to provide estimates of total pesticide usage.

The total area of arable crops grown in Northern Ireland in 2006 was 41,469 hectares. This represented a reduction of 15% compared to that recorded in 2004 and a 32% reduction to that recorded in the first pesticide usage survey on the arable sector in 1990. Approximately 43% of the arable cropping area was in County Down, 25% in County Londonderry, 16% in County Antrim, 9% in County Tyrone and 7% in County Armagh. There was no significant area of arable cropping in County Fermanagh.

Since the previous survey in 2004, the area of arable crops treated with pesticides decreased by 9%, to 295,635 spray-hectares. In the same period, the area treated with insecticides reduced by 13% but the weight of insecticide applications increased by 4%. This was due to the increased rate of application of the organophosphate, chlorpyrifos to cereal crops. The area treated with fungicides (12%) and herbicides/desiccants (10%) has decreased since 2004 and the weight applied of these pesticide groups also decreased by 5% and 40%, respectively. This reflects the relatively low dose rates of current herbicide applications. The molluscicide-treated area increased four-fold and by more than four-fold for weight applied. This was principally due to increased application of methiocarb, to maincrop potatoes for slug control. Growth regulators were applied primarily to spring barley, winter barley and, most frequently, to winter wheat. The use of growth regulators on cereal crops has increased by 19% when compared with 2004. The principal growth regulator used in 2006 was chlormequat, which is consistent with other recent surveys. The total weight of pesticides applied to arable crops in 2006 decreased to 238 tonnes of active ingredients, a reduction of 30% compared with 2004. As in 2004, the single active ingredients fludioxonil and imazalil, were the most commonly used seed treatments applied to cereals and potatoes, respectively.

Regional pesticide usage during 2006 was related to the area of arable crops grown in each county. Pesticides were applied to 83% of the total area of arable crops grown in Northern Ireland in 2006 with a range of 1.0 - 8.8 applications per crop.

Fungicides were applied to 42% of the pesticide-treated area, accounting for 28% of the total weight of pesticides used. Herbicides and desiccants were applied to 32% of the pesticide-treated area, representing 64% of the total weight of pesticides used.

Insecticides accounted for 10% of the pesticide-treated area of arable crops, representing less than 1% of the weight of pesticides used. Molluscicide treatments represented less than 1% of both area of application and weight of pesticides applied. Growth regulator usage accounted for 7% of the pesticide-treated area and 5% of the weight of active ingredients applied. Seed treatments were applied to 10% of the area of arable crops grown in 2006, representing 2% of the weight of active ingredients applied.

Potato crops comprised 12% of the area of arable crops grown in Northern Ireland in 2006, and accounted for 23% of the total pesticide-treated area. However, the weight of pesticides applied to potato crops represented 64% of the total weight of pesticides used on all arable crops. The total area of potatoes grown comprised 78% maincrop, 15% seed and 7% early potatoes. Potato crops accounted for 37% of the area of arable crops treated with fungicides and received 70% of the total weight of fungicides applied. Furthermore, applications of herbicides and desiccants to potato crops represented 17% and 67% of the area treated and weight applied of this pesticide group, respectively. The most commonly recorded fungicide was mancozeb, applied to arable crops as a single active ingredient and in formulation with other compounds. Mancozeb, used primarily in maincrop potatoes to control blight (Phytophthora infestans), accounted for 20% of the fungicide-treated area and 56% of the weight of fungicide active ingredients applied to this crop. Spring and winter barley crops accounted for 54% of the herbicide and desiccant-treated area, but only 18% of the weight applied of active ingredients from this pesticide group. The most commonly applied herbicide, used almost exclusively on cereal crops, principally spring barley, was metsulfuron-methyl. Owing to the low application rate of this active ingredient, the weight applied represented less than 1% of the total weight of herbicides and desiccants used.

A total of 262 products, comprising 114 active ingredients, was recorded in use on field crops in the survey.

In common with previous surveys of arable crops, data relating to post-harvest/storage treatments applied to farm stored potatoes were collected. An estimated 117,554 tonnes of potatoes were stored on-farm following the 2006 growing season. This represented a 24% decrease compared with 2004. Ware potatoes accounted for 79% of the total quantity of stored potatoes, with seed potatoes accounting for the remainder. County Londonderry and County Antrim accounted for 34% and 33% of all potatoes stored, respectively. All potatoes receiving treatments in storage were in County Down. Overall, less than 1% of stored potatoes received pesticide treatment. The protectant conazole fungicide imazalil was the only pesticide used with an estimated 0.76 kg of the active ingredient applied to 76 tonnes of stored seed potatoes in Northern Ireland in 2006. Approximately 43% of all potatoes in 2006 were stored in ‘ventilated’ stores. An estimated 77% of potatoes were stored on-farm in boxes, while 21% were stored in bulk.

For further information on this work please contact: Pesticide usage monitoring group