Pesticide Usage Report: Grassland and Fodder Crops 2021

SUMMARY

This is the ninth survey examining pesticide usage practices on grassland and fodder crops in Northern Ireland, providing comparative data to that obtained in the previous surveys in 1989 (Jess et al., 1992), 1993 (Jess et al., 1995), 1997 (Jess et al., 2000), 2003 (Withers et al., 2005), 2005 (Withers et al., 2007), 2009 (Withers et al., 2010), 2013 (Withers et al., 2014) and 2017 (Lavery et al., 2018).  Information on all aspects of pesticide usage was collected from 200 enclosed grassland, 55 arable silage, 23 fodder maize and 4 other fodder crop holdings throughout the province, representing 2.3% of the total area of grassland and fodder crops grown.  Quantitative data have been adjusted to provide estimates of total pesticide usage.  The total area of grassland and fodder crops grown in Northern Ireland in 2021 was an estimated 1,348,412 hectares.

Overall, the area of grassland and fodder crops grown in 2021 increased by 14% when compared to 2017.  The area of established grassland crops increased by 12% during this period and there was a 31% increase in the area of sown crops which included arable silage, arable silage (undersown) and all grass reseed areas up to five years old.  The area of fodder crops grown in Northern Ireland in 2021 increased by 52% compared to that recorded in 2017, primarily due to an increase in fodder maize and fodder kale production during this period.  Overall, grass silage production increased by 47% between 2017 and 2021.  A period of prolonged favourable weather, extending beyond the normal growing season into Autumn, allowed for an additional fifth and sixth cut of grass silage which was recorded for the first time in 2021. 

The area of grassland and fodder crops receiving pesticide treatments increased by 6% when compared to that recorded in 2017.  A total of 120,962 kilogrammes of pesticide active ingredients was applied to 153,560 spray hectares of grassland and fodder crops during 2021.  This represented a 22% increase in the weight of pesticides applied compared to 2017.  A total of 107 products comprising 55 active substances were recorded in use during this survey.  Herbicides accounted for 89% of the pesticide-treated area, representing 98% of the weight of pesticides applied.  Fungicides, Insecticides growth regulators and seed treatments collectively accounted for the remainder of the total pesticide usage and were applied to arable silage, arable silage (undersown), grass reseed and fodder crop areas.  No molluscicide use was recorded during this survey period.

The area of established grassland crops treated with pesticides increased by 1% when compared to 2017, however, the weight of active substances applied increased by 18% during the same period.  The area of sown crops treated with pesticides, primarily arable silage (undersown) and grass reseed, increased by 29% and the weight of active substances applied increased by 54%, consistent with the increased grown area of these crops.  The area of fodder maize grown in 2021 increased by 55% when compared with 2017 and, whilst the pesticide-treated area of these crops decreased by 8%, the weight applied increased by 18%.  The area of other fodder crops grown increased by 102%, specifically fodder kale, from 406 ha in 2017 to 1,149 ha in 2021.  Seed treatments were

the only active substances recorded as used on other fodder crops, with the non-systemic fungicide fludioxonil and the synthetic pyrethroid teflurthin being the only two applied.

In keeping with data from previous years, herbicides remain the most extensively used pesticide type on grassland and fodder crops.  During this survey period, the area treated with herbicides and the weight applied has increased by 4% and 23%, respectively, when compared with 2017. 

The five most commonly applied herbicides, either in formulation or as individual active substances, ranked by treated area (spha), were fluroxypyr, triclopyr, MCPA (2-methyl-4-chlorophenoxyacetic acid), mecoprop-P (methylchlorophenoxypropionic acid) and aminopyralid (figure 74a).  The five most commonly applied herbicides, ranked by weight (kg), were MCPA, triclopyr, glyphosate, fluroxypyr and mecoprop-P (figure 74b). 

An estimated 50% (29,384 spha) of Grass silage 1^st cut and 45% (16,527 spha) of enclosed grazing received herbicide treatments for control of docks (Rumex spp.).  The broad-spectrum systemic herbicide glyphosate was applied extensively to grass reseed areas for ‘ground preparation’.  MCPA, a selective phenoxy herbicide, was used to control a range of broadleaved weeds in established grassland crops including docks (Rumex spp.) and rushes (Juncus spp.) in both enclosed and rough grazing areas.