Pesticide usage report: Arable crops 2008

Summary

This is the tenth 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 (Jesset al., 2000), 1998 (Jess et al., 2002), 2000 (Withers et al., 2004), 2002 (Withers et al., 2004), 2004 (Withers et al., 2006) and 2006 (Withers et al., 2007).

Information on all aspects of pesticide usage was collected from 274 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 2008 was 46,337 hectares. This represented a increase of 12% compared to that recorded in 2006 and a 24% reduction compared to that recorded in the first pesticide usage survey of the arable sector, in 1990. Approximately 43% of the arable cropping area in 2008 was in County Down, 25% in County Londonderry, 17% in County Antrim, 8% in County Tyrone and 7% in County Armagh. This distribution is similar to that recorded in 2006. There was no significant area of arable cropping in County Fermanagh.

A total of 274 products, comprising 105 active ingredients, was recorded in use on field crops in the survey.

During the period 2006 to 2008, the area of arable crops treated with pesticides increased by 27%, to 374,207 spray-hectares. The use of insecticides increased by 39%, however the weight of application decreased by 25%. This was partly due to decreased applications of the organophosphate, chlorpyrifos to cereal crops. Applications of fungicides (30%) and herbicides/desiccants (23%) increased since 2006. The weight of fungicides applied also increased by 15% but due to the withdrawal of sulphuric acid, the weight of herbicides and desiccants applied decreased by 53%. Molluscicide applications remained similar to levels recorded in 2006 and 1998. An estimated 35% of molluscicide applications were to control slugs on maincrop potatoes. Growth regulators were applied primarily to spring barley, winter barley and most frequently to winter wheat. The use of growth regulators on cereal crops increased by 14% when compared with 2006. The principal growth regulator used in 2008 was chlormequat which is consistent with previous surveys conducted in 1998-2006. The total weight of pesticides applied to arable crops in 2008 decreased to 169 tonnes of active ingredients, a reduction of 29% compared with 2006. The formulation prochloraz/triticonazole was the most commonly applied seed treatment to cereals in 2008. This contrasted with 2004 and 2006 where the single active ingredient fludioxonil was the most commonly applied. In common with 2004 and 2006, imazalil was the most commonly used seed treatment applied to potatoes.

During 2008, regional pesticide usage was related to the area of arable crops grown in each county. Pesticides were applied to 98% of the total area of arable crops grown in Northern Ireland in 2008 with a range of 1.0 – 9.7 applications per crop.

Fungicides were applied to 43% of the pesticide-treated area, accounting for 46% of the total weight of pesticides used. Herbicides and desiccants were applied to 31% of the pesticide-treated area, representing 42% 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 6% of the pesticide-treated area and 10% of the weight of active ingredients applied. Seed treatments were applied to 10% of the area of arable crops grown in 2008, representing 1% of the weight of active ingredients applied.

Potato crops comprised 12% of the area of arable crops grown in Northern Ireland in 2008, while accounting for 21% of the total pesticide-treated area. However, the weight of pesticides applied to potato crops represented 34% of the total weight of pesticides used on all arable crops. This was a reduction from previous years due to the withdrawal of sulphuric acid as a haulm desiccant. The total area of potatoes grown comprised 78% maincrop, 14% seed and 7% early potatoes. Potato crops accounted for 33% of the area of arable crops treated with fungicides and received 58% of the total weight of fungicides applied. Furthermore, applications of herbicides and desiccants to potato crops represented 17% of both the area treated and weight applied of this pesticide group. The most commonly recorded fungicide applied to potato crops was fluazinam, applied mainly as a single active ingredient but also in formulation with metalaxyl-M. Fluazinam was used on 12% of the fungicide-treated area and accounted for 4% of the weight of fungicide active ingredients applied. It was used primarily in maincrop potatoes to control blight (Phytophthora infestans) and for general disease control. Chlorothalonil, applied mainly as a single active ingredient but also in formulation, was the most frequently applied fungicide to cereal crops. Due to the inclement weather at harvest time, the most frequently applied herbicide and desiccant used on cereal crops, principally spring barley, was glyphosate. It accounted for 22% of the area of arable crops treated with herbicides and desiccants and 33% of the total weight of herbicides and desiccants applied.

This was the sixth survey in which the cultivation of pea and bean crops was recorded.

In addition to information concerning field applications of pesticides to crops, data relating to post-harvest/storage treatments applied to farm stored potatoes were collected. It was estimated that 70,794 tonnes of potatoes were stored on-farm following the 2008 growing season. This represented a 40% decrease compared with 2006. Ware potatoes accounted for 85% of the total quantity of stored potatoes, with seed and early potatoes equally distributed in the remainder. County Down and County Londonderry accounted for 31% and 27% of all potatoes stored, respectively. All potatoes receiving treatments in storage were in County Londonderry. Overall, approximately 7% of stored potatoes received pesticide treatment. The sprout suppressant chlorpropham was the only pesticide used with an estimated 173 kg applied to 4,680 tonnes of stored ware potatoes in Northern Ireland in 2008. Approximately 38% of all potatoes in 2008 were stored in ‘ventilated’ stores. Overall, 87% of potatoes were stored on-farm in boxes, while 12% were stored in bulk.

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