A new candidate biological control agent for the control of Pereskia aculeata Miller (Cactaceae) in South Africa

A new candidate biological control agent for the control of Pereskia aculeata Miller (Cactaceae) in South Africa
Lumka A. MDODANA1, Iain D. Paterson1, Steve Compton1,2
1Biological Control Research Group, Department of Zoology & Entomology, Rhodes University, Grahamstown, 6140 South Africa
2School of Biology, University of Leeds, LS29JT, UK

Pereskia aculeata Miller (Cactaceae) is an invasive alien plant in South Africa that is a threat to indigenous biodiversity. Pereskiophaga brasilensis Anderson (Curculionidae) is a promising potential biological control agent for P. aculeata that has been imported from the native distribution of southern Brazil into quarantine in South Africa for host specificity testing. The adults of P. brasilensis feed on the leaves and shoot tips of P. aculeata and the larvae mine inside the stems, destroying the vascular tissue. Thirty test plant species from eight closely related families have been tested in no-choice oviposition trials and no development was recorded on any of the test plant species. Larval no-choice tests were also conducted in which larvae hatched on P. aculeata were transferred to test plant species and P. aculeata controls. Fifteen plant species have been included in these tests and feeding and survival was only recorded on P. aculeata. Pereskiophaga brasilensis also had a significant impact on P. aculeata growth parameters. Shoot length was significantly reduced in plants exposed to P. brasilensis by an average of 11.9 cm (±2.07), (T test; t = -42.9, p<0.001), and the average number of leaves was also reduced by 45.3 leaves (±11.9), (T test; t = -4.65, p<0.001). An application for release is being prepared and will be submitted to the relevant authorities. This new agent could significantly impact P. aculeata in South Africa and help protect indigenous biodiversity