The successful biological control of Cylindropuntia fulgida var. mamillata (A. Schott ex Engelm.) Backeb. (Cactaceae) (coral or boxing glove cactus) at two field sites in Queensland, Australia

Abstract

Cylindropuntia fulgida var. mamillata (A. Schott ex Engelm.) Backeb. (Cactaceae) (coral or boxing glove cactus) is one of eight invasive species of Cylindropuntia in Australia that have been targeted for biological control. The ‘cholla’ lineage of Dactylopius tomentosus (Lamarck) (Hemiptera: Dactylopiidae) was first released in South Africa in 2008. This lineage is the second of a series of host-specific cochineal insects to be released to control Cylindropuntia species in Australia and was selected to target C. fulgida var. mamillata. Approval to field release this lineage was granted in November 2015 and the cochineal was first released at Leander Station, near Longreach, Queensland in March 2016 and at Booligar Station, near Hebel, Queensland in April 2016. An intensive monitoring program was undertaken at both sites to evaluate the establishment, rate and direction of spread and impact of the D. tomentosus ‘cholla’ lineage on C. fulgida var. mamillata. The cochineal established very well at Leander Station but needed to be re-released at Booligar Station following heavy rain and flooding soon after the first release. Once established, populations of the cochineal at both sites built up very quickly and spread with the prevailing winds, infesting 100% of plants at each of the monitoring sites within 14 months of release. The impact on plants was substantial, with 95% of plants dying at Leander Station within 19 months of the cochineal being released. At Booligar Station, about 98% of plants had died within 18 months of the second cochineal release. Of the plants that were still alive, all had been severely damaged by the cochineal and were showing signs of poor health. These results and observations at other release sites, both in Australia and South Africa, suggest D. tomentosus ‘cholla’ lineage should be an effective agent for the control of C. fulgida var. mamillata.