The biology and host plant relationships: the grass aphid Metopolophium festucae (Theobald), subspecies cerealium

Metopolophium festucae s.str. is restricted to grasses whilst the subspecies M. festucae cerealium has extended its host range to include cereals. This study considers only M. festucae cerealium. The performance of this aphid on a range of host plants has been considered in terms of antibiotic and antixenotic resistance. Particular emphasis was placed on the comparative resistance of wheat and L. perenne. M. festucae cerealium was more fecund on wheat, produced more alatae and showed more restlessness than on L. perenne. The difference in response on the two host plants implicated the influence of secondary plant substances in wheat. The role of the grassland habitat was considered in relation to density independent induction of alatae and the general life history strategy of this aphid. The influence of temperature on M. festucae cerealium was investigated, and was found to influence reproductive performance, the induction of alate virginoparae and the morphology of virginoparae. Temperature did not influence the aphid's ovariole number and did not induce the development of any sexual morphs. M. festucae cerealium was considered to be anholocyclic on Gramineae. The control of M. festucae cerealium in grassland and the implications of its life history strategy for integrated control are discussed.