Individual study: Effects of different intensities of fertilizers and pesticides on aphids and aphid predators in winter wheat
Hasken K.H. & Poehling H.M. (1995) Effects of different intensities of fertilizers and pesticides on aphids and aphid predators in winter wheat. Agriculture, Ecosystems & Environment, 52, 45-50
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Reduce fertilizer, pesticide or herbicide use generally
A small replicated controlled trial at two sites in Lower Saxony, Germany (Hasken & Poehling 1995) found that aphids (Aphidoidea) and their insect predators were less abundant in wheat fields not treated with fertilizers, insecticides or herbicides in 1992, compared to conventionally farmed fields or fields with low fertilizer use and no insecticide. A maximum of 80 aphids/wheat stem were recorded on plots with no chemicals, compared to 300 aphids/stem in the conventional farm system and close to 300 aphids/stem in fields with a 50% reduction in nitrogen fertilizer application (105 kg N/ha, compared to the conventional 210 kg N/ha) and no insecticide (herbicides were used). Fields with no chemical use had no more than 20 aphid predator larvae/m2; hoverflies (Syrphidae), ladybirds (Coccinellidae) and lacewings (Chrysopidae), compared with up to 60-70 larvae/m2 under conventional farming and up to 40 larvae/m2 with 50% fertilizer reduction and no insecticide. Under conventional farming, ladybirds were only recorded on plots not treated with insecticide. In farming systems with reduced or no chemical use, ladybirds were the dominant aphid predator in most months. This study was carried out on areas of 35 to 45 ha at two sites (two replicates of each farming system). Aphids and their predators were counted on 150 wheat stems twice a week and suction trapped every two weeks during the 1992 growing season. This study was part of the same project (INTEX – Integrated Farming and Extensification of Agriculture) and was carried out in partly the same research site as (Schmidt et al. 1995, Krooss & Schaefer 1998).