The effects of agrochemicals on Lepidoptera, with a focus on moths, and their pollination service in field margin habitats

Published source details 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.
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This study is summarised as evidence for the following.

	Action	Category
	Restrict certain pesticides or other agricultural chemicals Action Link
	Reduce fertilizer, pesticide or herbicide use generally Action Link

Restrict certain pesticides or other agricultural chemicals

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.

(Summarised by: Andrew Bladon)
Reduce fertilizer, pesticide or herbicide use generally

A replicated, randomized, paired, controlled study in 2010–2011 in an extensively managed hay meadow in Landau, Germany (Hahn et al 2015) found that plots without insecticide applied had higher caterpillar abundance than plots with insecticide, but the application of herbicide did not alter caterpillar abundance, and plots without fertilizer had lower caterpillar abundance in one of two sampling sessions. In plots not treated with insecticide, caterpillar abundance (1–2 individuals/plot) was higher than in plots with insecticide applied (0 individuals/plot). However, caterpillar abundance was lower in plots not treated with fertilizer (1–2 individuals/plot) than in plots with fertilizer applied in one of two samples (2–3 individuals/plot). Caterpillar abundance was similar in plots without (1–2 individuals/plot) and with (2 individuals/plot) herbicide applied. The results were mostly due to differences in the numbers of two moth groups (Geometridae and Noctuidae). In 2010, sixty-four plots (8 × 8 m) were assigned to one of eight treatments: no pesticide, herbicide or fertilizer, insecticide-, herbicide- or fertilizer-only, or each combination of two or three chemicals applied. Fertilizer was applied twice/year in April, with a granular nitrate/phosphorus/potassium fertilizer and a calcium carbonate/ammonium nitrate fertilizer two weeks apart. Herbicide (Atlantis WG) was applied once/year in April. Insecticide (Karate Zeon) was applied once/year in late May or early June. On 30 May and 27 June 2011, caterpillars were sampled using sweep nets (80 and 100 sweeps/plot).

(Summarised by: Andrew Bladon)