BIOLOGICAL INVESTIGATIONS INTO THE VALIDITY OF<i>CONTARINIA</i>SPECIES LIVING ON THE CRUCIFERAE, WITH SPECIAL REFERENCE TO THE SWEDE MIDGE,<i>CONTARINIA NASTURTII</i>(KIEFFER)*

Abstract

Biological investigations have proved that Contarinia nasturtii (Kieffer), C. isatidis Rübsaamen and C. ruderalis (Kieffer) are in reality one species. The names C. isatidis Rübsaamen and C. ruderalis (Kieffer) are therefore synonyms of C. nasturtii (Kieffer). Considerable doubt has been thrown on the authenticity of several other species. The host plant range of C. nasturtii was already known to be very extensive. Fourteen additional host plants, including two tetraploid varieties and several weeds have been added during this investigation. Eight were established by experiments, and the remaining six have previously been recorded as host plants of C. ruderalis . In addition, Brassica nigra, Lepidium sativum and Rapistrum rugosum have since been established as host plants of Contarinia nasturtii in Holland. Diplotaxis tenuifolia and Lunaria annua are suspected as host plants, but the evidence is not yet conclusive.