A series of behavioral assays investigated the impact of peach (Prunus persica) extrafloral nectar on the longevity and fecundity of the predator Harmonia axyridis. Field experiments also evaluated the effect of extrafloral resource provision on the adult beetle’s effectiveness as an aphid biocontrol agent. The results indicate that over short time frames (i.e., <24h), beetles consuming extrafloral nectar may be detracted from aphid prey, resulting in an initial reduction in aphid mortality. However, the provision of extrafloral nectar directly benefits H. axyridis development and is likely to augment aphid biological control over the longer term, through an enhanced numerical response.