Hosts parasitized by different species of the Korthalsella genus throughout its global distribution belong mostly to the following families: Apocynaceae, Aquifoliaceae, Celastraceae, Ebenaceae, Elaeocarpaceae, Epacridaceae, Ericaceae, Euphorbiaceae, Lauraceae, Mimosaceae, Myrsinaceae, Myrtaceae, Oleaceae, Rubiaceae, Rutaceae, Sapindaceae and Sapotaceae. Only one Korthalsella species is known to parasitize gymnosperms (i.e., K. dacrydii parasitic on Dacrydium and Podocarpus in Malesia).
Published host records for New Zealand’s pygmy mistletoes include members of Apiaceae, Araliaceae, Asteraceae, Elaeocarpaceae, Epacridaceae, Ericaceae, Fabaceae, Myrsinaceae, Myrtaceae, Pittosporaceae, Polygonaceae, Rhamnaceae and Rubiaceae. The complete list of published host records for New Zealand Korthalsella species is as follows:
Korthalsella clavata
Favoured hosts include Coprosma propinqua, Aristotelia fruticosa followed by Discaria toumatou. Coprosma crassifolia, C. linariifolia, C. pedicellata, Melicope simplex, Muehlenbeckia australis, Myrsine australis, Olearia solandri and Pittosporum tenuifolium are sometimes also parasitized.
Korthalsella lindsayi
Melicope simplex is the most favoured host followed by Lophomyrtus obcordata. Coprosma areolata, C. crassifolia, C. rhamnoides, C. rigida, C. rotundifolia, C. rubra, C. virescens, Discaria toumatou, Helichrysum glomeratum (=H. lanceolatum), Ileostylus micranthus, Lophomyrtus bullata x obcordata, Metrosideros spp., Muehlenbeckia astonii, M. australis, M. complexa, Myrsine australis, Olearia solandri, Pittosporum obcordatum, Pseudopanax ferox, Scandia geniculata and Sophora spp. are sometimes also parasitized.
Korthalsella salicornioides
Leptospermum scoparium var. scoparium (manuka) is the favoured host followed by Kunzea ericoides var. ericoides (kanuka). Dracophyllum sp., the exotics Erica lusitanica and E. vagans, Gaultheria sp., Myrsine australis, Sophora chathamica, Coprosma rhamnoides, C. tenuicaulis and Melicope simplex are sometimes also parasitized.