The Initiation of a Biological Control Programme Against Pompom Weed,Campuloclinium macrocephalum(Less.) DC. (Asteraceae), in South Africa

Abstract

Pompom weed, Campuloclinium macrocephalum (Less.) DC. (Asteraceae), is a South American invasive plant that was first recorded in South Africa in the early 1960s. In the 1980s, C. macrocephalum started slowly extending its range and in the 1990s and 2000s it entered a dramatic expansion phase. It invades grasslands, savannas and wetlands where it has a significant impact on biological diversity. Control of C. macrocephalum has, so far, been based on herbicides, as mechanical approaches were found to exacerbate infestations through disturbance. However, due to the extent of the invasion, the financial and environmental costs of treating all C. macrocephalum infestations with herbicides would be prohibitive. As a result, a biological control programme was initiated against the weed in 2003. Surveys conducted on C. macrocephalum in its native range, indicated that northern Argentina has the highest diversity of natural enemies associated with the plant. Three insect species, Zeale (=Adesmus) nigromaculatus Klug (Coleoptera: Cerambycidae), Liothrips tractabilis Mound & Pereyra (Thysanoptera: Thripidae) and Cochylis campuloclinium Brown (Lepidoptera: Tortricidae), and one pathogen, Puccinia eupatorii Dietel (Pucciniales: Pucciniaceae) were rated (based on damage, range and abundance) as having the most potential as biological control agents for C. macrocephalum. This paper is a review of the biology, host range and potential impacts of these agents, as well as the prospects for the control of C. macrocephalum in South Africa.