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Do natural enemies really make a difference? Field scale impacts of parasitoid wasps and hoverfly larvae on cereal aphid populations
Author(s) -
Ramsden Mark,
Menendez Rosa,
Leather Simon,
Wäckers Felix
Publication year - 2017
Publication title -
agricultural and forest entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.755
H-Index - 55
eISSN - 1461-9563
pISSN - 1461-9555
DOI - 10.1111/afe.12191
Subject(s) - biology , aphid , pest analysis , predation , parasitoid , biological pest control , population , ecology , integrated pest management , abundance (ecology) , agronomy , pest control , beneficial insects , botany , demography , sociology
Naturally occurring predators and parasitoids are known to reduce the abundance of pest invertebrates in arable crops, yet current treatment thresholds do not account for such a contribution to pest management. In the present study, we provide evidence for the presence of natural enemies correlating with a subsequent reduction in pest population growth. The abundance of cereal aphid pests and two key aphidophagous natural enemies, parasitoid wasps ( A phidiinae) and hoverfly larvae ( S yrphinae), was assessed at field boundaries and interiors in southeast E ngland. The highest rate of aphid population growth was associated with locations where no natural enemies were found. The presence of either A phidiinae wasps or predatory S yrphinae larvae was associated with a reduction in the rate of aphid population growth, irrespective of location within the field, and overall aphid population growth was negatively correlated with increasing natural enemy abundance. The results of the present study indicate that natural enemies contribute significantly to pest control, and provide further evidence supporting the use of management strategies for promoting natural enemies in agro‐ecosystems. Aphid predators and parasitoids make an important contribution to aphid pest control within cereal fields, and thresholds for insecticide application should account for this to avoid unnecessary treatments.