Understanding invasions and pest risks in agriculture: Current research status on invasive fruit flies (Diptera: Tephritidae) and new directions for management and intervention planning in South Africa
Minette Karsten1, Madeleine G. Barton2, Pia Addison2, Matthew F. Addison2, John S. Terblanche1
1Centre for Invasion Biology, Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
2Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
Research in the field of biological invasions has increased dramatically in the last two decades, especially due to the impact of human activity such as, transport, travel and international trade. Therefore, developing a general management framework for monitoring and reporting biological invasions based on past research are crucial to assist decision making and actions to be taken. Here we make use of a range of different datasets for significant economic agricultural fruit fly pests to gain insight into potential intervention strategies. First we review the pest and invasion status, economic impact and current control of fruit flies in South Africa. Then we highlight the importance of monitoring data and how timing and location can influence monitoring outcomes. Moreover we show the importance of accurate identification of new interceptions and discuss some challenges in doing so. Furthermore we illustrate that once a species has been correctly identified as an invader, information on invasion pathways can be used to identify, monitor, reduce and, ultimately, remove existing or potential new, movement pathways, hindering the continued spread of the pest. Finally, once a species is established in a new area natural dispersal becomes an important consideration in the subsequent spread of the species. We demonstrate how population genetic estimates of landscape structure can provide insight into management units, and test whether the landscape offers any intrinsic resistance to this movement (e.g. natural barriers). Using fruit flies we illustrate the concepts outlined above in a management decision flowchart/tree for integrating pest management and invasion management into a common framework.