Suction-trap catches partially predict infestations of the grain aphid Sitobion avenae in winter wheat fields

Effective pest monitoring programmes are needed for providing reliable advice on when pest populations require active management. We studied whether suction-trap catches of the grain aphid Sitobion avenae during the period 1989-2009 can be used to predict field infestations of this aphid in Swedish winter wheat fields. We found that suction-trap catches of S.avenae until the time of crop heading (GS51) were significantly related to both number of aphids per tiller (R-2=0.69 at GS 59 and R-2=0.27 at GS 69) and proportion of fields with infestations above economic threshold (R-2=0.49 at GS 59 and R-2=0.40 at GS 69). This effect was consistent across Swedish regions and years. This information could be used by advisory services and farmers to decide whether field inspection to estimate the profitability of insecticide treatment at heading is needed. To improve the predictive ability further, suction-trap catches could be combined with weather data and information about biological control potential in different landscapes