DNA sequence data confirms the presence of two closely related cypress-feeding aphid species on African cypress (Widdringtonia spp.) in South Africa

Abstract

Aphids in the genus Cinara (Hemiptera: Aphididae) are pests of coniferous trees globally. Some of these aphids have become invasive in various parts of the world and have led to significant economic and environmental damage. During surveys conducted as part of a sentinel plant project, severe aphid infestations were observed on Widdringtonia trees in the Kirstenbosch National Botanical Garden, Cape Town, South Africa. In addition, planted Widdringtonia wallichii Endl. ex Carrière trees within their natural range of the Cederberg Wilderness Area, Western Cape, South Africa were found infested with aphids. In this study, we investigated the species identity of the aphids using DNA sequence data for the mitochondrial cytochrome coxidase (COI) gene. The results revealed the presence of two closely related aphid species, the cypress aphid, Cinara cupressi (Buckton) and the cypress pine aphid, Cinara tujafilina (Del Guercio) infesting Widdringtonia spp. in South Africa. Both aphid species are alien to South Africa. While this is not the first report for either species in the country, the current study provides evidence of impact, with severe infestations leading to branch dieback and tree death. This finding supports the regulation of Cinara spp. in South Africa and highlights that management is urgently needed.