Biodiversity in glyphosate tolerant fodder beet fields: Timing of herbicide application

Published source details Strandberg B. & Bruus Pederson M. (2002) Biodiversity in glyphosate tolerant fodder beet fields: Timing of herbicide application. Department of Terrestrial Ecology, National Environmental Research Institute (Silkeborg, Denmark) report, NERI Technical Report 410.
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This study is summarised as evidence for the following.

	Action	Category
	Delay herbicide use Action Link

Delay herbicide use

A randomised, replicated, controlled study in 2001 on Mors, Denmark (Strandberg & Bruus Pederson 2002) found more ladybird (Coccinellidae) and sawfly larvae (Symphyta) in mid-July in plots receiving late applications of herbicide (averaging 1.80 and larvae/0.9 m², respectively) at recommended (0.30 and 0.2 larvae) or early (0.05 and 0.05 larvae) spraying dates. More rove beetles (Staphylinidae), adult ground beetles (Carabidae) and money spiders (Linyphiidae) also occurred when plots were sprayed late (42 rove beetles, 6 ground beetles and 33 money spiders/0.9 m²) rather than at recommended (19, 3 and 28, respectively) or early dates (18, 3 and 22). Rove beetles and money spiders showed similar patterns in mid-June. Groups that did not show an effect were not presented. Some pest groups such as planthoppers (Delphacidae) and leaf beetles (Chrysomelidae) were also more numerous in plots sprayed late. Plots treated later had more weeds (0.2-52.3 weeds/m²) than plots treated at recommended or early dates (0.6-18.8 and 0.1-5.7 weeds, respectively). Beet Beta vulgaris yields were similar between treatments (870-970 t root/ha). Glyphosate was sprayed in three timing treatments: early application (25 May and again 27 June), recommended application (14 June and 5 July) and late application (27 June and 16 July).