Enhancement of generalist aphid predators in cereals: effect of green manuring on recruitment of ground beetles

Published source details Helenius J. & Tolonen T. (1994) Enhancement of generalist aphid predators in cereals: effect of green manuring on recruitment of ground beetles. IOBC/wprs Bulletin, 17, 201-210.
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This study is summarised as evidence for the following.

	Action	Category
	Undersow spring cereals, with clover for example Action Link

Undersow spring cereals, with clover for example

A replicated, controlled, randomized study of an undersown cereal field from 1989 to 1991 in Helsinki, Finland (Helenius & Tolonen 1994) found that green manuring with undersown rye grass Lolium spp. resulted in a 50% increase in new generation adult ground beetles (Carabidae). A total of 33 species of ground beetles were caught. For three of the most common species, plots that had received rye grass green manuring (0.5 t/ha) in autumn 1990 resulted in a 50% increase in new generation adults in 1991 compared to mono-cropped plots (Trechus discus: 681 vs 442, Clivina fossor: 160 vs 137, Bembidion guttula: 108 vs 61). Rye grass provided more green manure than clover Trifolium spp. (49-412 vs 216-474 g/m²). A 1 ha block of the field was divided into 25 x 25 m plots with treatments in a 4 x 4 Latin square design. Clover or grass were sown straight after the cereal and were ploughed into the soil as a green manure in the autumn. Plant biomass was sampled within 0.25 x 0.5 m quadrats just before ploughing. Emergence rates of ground beetles were sampled using enclosures (0.5 x 0.5 m²) with four pitfall traps. Traps were emptied every seven days over a sequence of three (1989) or five (1990 and 1991) trapping periods of approximately one month (June-September).