Restrict certain pesticides or other agricultural chemicals

Supporting evidence from individual studies

1. A replicated, randomized, site comparison study in 1989–1991 in Oxfordshire, UK (Feber et al. 1994, same experimental set-up as Feber et al. 1996) found more adult meadow brown Maniola jurtina on naturally regenerated field margins that were not sprayed with herbicide than on margins which were sprayed once a year. After 1–2 years of herbicide application, there were more adult meadow brown on cut or uncut margins which were not sprayed (4–10 individuals/50 m) than on uncut sprayed margins (3–4 individuals/50 m). In the first year of herbicide application, there was no difference between unsprayed (7–15 individuals/50 m) and sprayed margins (15 individuals/50 m). In October 1987, two-metre-wide field margins around arable fields were rotovated and left to naturally regenerate. Fifty-metre-long plots were either uncut and unsprayed, subject to one of four different cutting regimes but unsprayed, or uncut but sprayed once/year with herbicide (glyphosate, 3 l/ha Roundup^TM in 175 l water) in late June or early July 1989–1991. There were eight replicates of each treatment. From June–September 1989, and April–September 1990–1991, adult meadow brown were monitored weekly.

   Study and other actions tested

   Referenced paper

   Feber R.E., Smith H. & Macdonald D.W. (1994) The effects of field margin restoration on the meadow brown butterfly (Maniola jurtina). British Crop Protection Council Monographs, 58, 295-300.

2. A replicated, randomized, site comparison study in 1989–1991 in Oxfordshire, UK (Feber et al. 1996, same experimental set-up as Feber et al. 1994) found that butterfly abundance and species richness were higher on naturally regenerated field margins that were not sprayed with herbicide than on margins which were sprayed once a year. After one year of herbicide application, both the abundance (39 individuals/50 m) and species richness (8 species/50 m) of butterflies were higher on uncut margins which were not sprayed than on uncut sprayed margins (abundance: 18 individuals/50 m; richness: 6 species/50 m). After two years of herbicide application, there were more butterflies on both cut and uncut margins which were not sprayed (abundance: 17–37 individuals/50 m; richness: 8–9 individuals/50 m) than on uncut sprayed margins (abundance: 12 individuals/50 m; richness: 7 species/50 m). In the first year of herbicide application, there was no difference between unsprayed (abundance: 15–44 individuals/50 m; richness: 6–9 species/50 m) and sprayed margins (abundance: 42 individuals/50 m; richness: 6 species/50 m). Two-metre-wide field margins around arable fields were rotovated in October 1987 and left to naturally regenerate. Fifty-metre-long plots were either uncut and unsprayed, subject to one of four different cutting regimes but unsprayed, or uncut but sprayed once a year with herbicide (glyphosate, 3 l/ha Roundup^TM in 175 l water) in late June or early July 1989–1991. There were eight replicates of each treatment. Butterflies were monitored weekly from June–September 1989 and from April–September 1990 and 1991.

   Study and other actions tested

   Referenced paper

   Feber R.E., Smith H. & Macdonald D.W. (1996) The effects on butterfly abundance of the management of uncropped edges of arable fields. Journal of Applied Ecology, 33, 1191-1205.

3. A replicated, randomized, controlled study in 2008–2009 on two arable farms in Berkshire, UK (Blake et al. 2011) found that grass buffer strips which were not sprayed with grass-specific herbicide had a similar abundance and species richness of butterflies to sprayed strips. On unsprayed grass buffer strips, the abundance (3.7 individuals/plot), species richness (3.7 species/plot) and diversity of butterflies was not significantly different to strips which had been sprayed with herbicide (abundance: 2.2 individuals/plot; richness: 2.5 species/plot; diversity presented as model results). Six-metre-wide grass buffer strips were created on two arable farms in 2004 and managed under an Entry Level Stewardship agreement from 2005. In April 2008, three pairs of 25 × 4 m plots were established at each farm. One random plot/pair was sprayed with a grass-specific herbicide (“fluazifop-P-butyl”), and the other was left unsprayed. All plots were cut to 15 cm in autumn, and cuttings left in place. From May–September 2008–2009, butterflies were surveyed twice on each of four days/year on a 25-m transect through the centre of each plot.

   Study and other actions tested

   Referenced paper

   Blake R., Woodcock B., Westbury D., Sutton P. & Potts S. (2011) New tools to boost butterfly habitat quality in existing grass buffer strips. Journal of Insect Conservation, 15, 221-232.

4. A controlled study in 2012 in a field in Landau, Germany (Hahn et al 2015) found more eggs and caterpillars of the lychnis moth Hadena bicruris on white campion Silene latifolia alba flowers which had been sprayed with water than on flowers sprayed with insectide. After a single night, flowers sprayed with water had more lychnis moth eggs and caterpillars (18 individuals) than flowers sprayed with insecticide (11 individuals). White campion were grown from seed and cultivated indoors in 10 cm pots before being potted into 2 litre containers and moved outside. In September 2012, after flowering began, six female plants were sprayed with water, six were sprayed with insecticide (Karate Zeon), and all were placed outside, 1 m apart, around the circumference of a 2-m radius circle. Six male plants were sprayed with water and placed in a smaller, 0.75-m radius circle inside the female plants. The plants were exposed to natural pollination overnight. The next morning, each flower was wrapped in gauze to exclude further pollination. Nine days later, the flowers were searched for eggs or caterpillars.

   Study and other actions tested

   Referenced paper

   Hahn M., Schotthöfer A., Schmitz J., Franke L.A. & Brühl C.A. (2015) The effects of agrochemicals on Lepidoptera, with a focus on moths, and their pollination service in field margin habitats. Agriculture, Ecosystems & Environment, 207, 153-162.

5. A replicated, site comparison study in 2016 on three rice farms in Pavia province, Italy (Giuliano et al 2018) found that herbicide-free rice field banks had a higher abundance and species richness of butterflies than banks which were sprayed with herbicide. On unsprayed banks, the abundance (1.2–12.2 individuals/100 m) and species richness (0.7–2.6 species/100 m) of butterflies was higher than on banks sprayed with herbicide once/year (abundance: 0.1–2.3 individuals/100 m; richness: 0.1–1.1 species/100 m). Endangered large copper Lycaena dispar butterflies were present on more unmanaged banks (48 individuals) than on sprayed banks (10 individuals). See paper for other species results. Banks (1–2 m wide) between paddy fields on three farms were either sprayed with herbicide (Glyphosate) in April, or left unmanaged with permanent herbaceous cover. From April–September 2016, butterflies were surveyed monthly on 160–440-m-long transects on 17 field banks (13 sprayed, four unsprayed).

   Study and other actions tested

   Referenced paper

   Giuliano D., Cardarelli E. & Bogliani G. (2018) Grass management intensity affects butterfly and orthopteran diversity on rice field banks. Agriculture, Ecosystems & Environment, 267, 147-155.