Rice root aphids, <i>Rhopalosiphum rufiabdominale,</i> and cannabis aphids, <i>Phorodon cannabis</i> (Hemiptera: Aphididae), are parasitised by <i>Aphelinus varipes</i> (Hymenoptera: Aphelinidae)

Abstract While an experimental colony of rice root aphids, Rhopalosiphum rufiabdominale (Sasaki) (Hemiptera: Aphididae) was being reared, hymenopteran parasitoids found their way into the colony and caused substantial aphid mortality. We identified the parasitoids as Aphelinus varipes (Förster) (Hymenoptera: Aphelinidae) and further investigated the ability of A. varipes to parasitise rice root aphids and cannabis aphids, Phorodon cannabis Passerini (Hemiptera: Aphididae), both pests of commercial cannabis plants, Cannabis sativa Linnaeus (Cannabaceae). In experiments with different densities of aphid hosts, female A. varipes parasitised both rice root aphids and cannabis aphids. The rate of parasitism did not exceed 21% for either aphid species but may exceed this in unconstrained operational settings. Aphelinus varipes should be investigated further as a potential biocontrol agent of rice root aphids and cannabis aphids.