Influence of the surrounding landscape on the colonization rate of cereal aphids and phytovirus transmission in autumn
Résumé
Ecological control has often focused on factorsenhancing control of pests by their natural enemies, whilefactors reducing the colonization rate of crops by pestshave been comparatively neglected. We present anapproach to assess landscape influence on the intensity ofwheat colonization by a major crop pest, the aphidRhopalosiphum padi. We used trays containing wheatseedlings to monitor field colonization by R. padi andbarley yellow dwarf viruses’ transmission in two areas inFrance in autumn. We assessed the influence of landscapecomponents likely affecting aphid colonization, i.e. maizeand grasslands as source of migrants on the number ofaphids landing per tray, as well as the host plant of originand the viruliferous potential of migrants. During the survey,maize was the main source of migrants. Virus transmissionwas detected in a few cases (4 % positive assays).Colonization was increased by the presence of maize, butreduced by the presence of grasslands at the landscapescale considered here (i.e. at a radius of 1000 m). Our studycontributes to a better understanding of disease dynamicsin agricultural landscapes. By identifying features of thelandscape that surrounds fields and affects these dynamics,growers can develop more efficient crop protection strategiesrelying on habitat manipulation and rational use ofpesticides.