Precocious activity of parasitoids is a key factor for cereal aphid control. We investigated the oviposition, flight and walking capacities at low temperature of four aphid parasitoids (Aphidius rhopalosiphi, A. ervi, Praon volucre, P. gallicum) on one of their aphid hosts (Sitobion avenae). Oviposition behaviour was tested at 2, 4, 6, 8, 10, 15 and 20[degree]C, under a photoperiod of 12 h light. Some females of A. rhopalosiphi oviposited at 6[degree]C while the percentage of parasitization below 10[degree]C remained low for the other species. The proportion of mates decreased with temperature for A. ervi, P. volucre and P. gallicum but not for A. rhopalosiphi. For all species, flight and walking activities increased with temperature, Aphidius species being active at lower temperature than Praon species. Field captures showed that the activity threshold for A. rhopalosiphi is 12[degree]C, 15[degree]C for A. ervi and P. volucre, and 19.5[degree]C for P. gallicum. These results are discussed regarding the potential of these four species for aphid control. Reproduction; Reproductive behaviour; Locomotion; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Abiotic factors; Physical factors; Land zones; Palaearctic region; Eurasia; Europe Aphidius ervi; Aphidius rhopalosiphi; Praon gallicum; Praon volucre (Aphidiidae ); Egg laying; Oviposition; Flight; Walking; Hemipteran hosts; Sitobion avenae; Temperature; Low temperature effect on oviposition, flight & walking capacities & prevalence on hemipteran host; Belgium; Brabant; Low temperature effect on parasitoid activity & parasitism levels on hemipteran host Sitobion avenae (Aphidoidea); Hymenopteran parasites; Aphidiinae; Low temperature effect on oviposition, flight & walking capacities of parasitoids & parasitism level; Temperature; Belgium; Brabant; Low temperature effect on hymenopteran parasitoid activity & parasitism levels none