Annual Report 2006/07 - ETH - North-South Centre North-South ...

Research fellowApollin Fotso Kuate, IITA CameroonSupervisorsPeter Nagel, University of Basel /Rachid Hanna, IITA, BeninCollaboratorsMaurice Tindo, IITA, Cameroon /Georg Goergen, IITA, BeninDurationNovember 2006 – October 2009Research Fellow Partnership Programme (RFPP)Options for controlling African root and tuber scaleon cassava in Central Africa – Understanding theecology of the associated ant Anoplolepis tenellaAnoplolepis tenella is an afro-tropical ground-dwelling antspecies with widespread distribution in the forest zones ofCentral Africa, where it is largely found in association withthe African Root and Tuber Scale (ARTS) Stictococcus vayssiereiRichard, an emerging pest of cassava in Central Africa. Amajor effort is presently underway to identify factors thataffect the abundance of ARTS, and to develop sustainablepractices for its management on cassava and other affectedfood crops. While the nature of the interactions betweenA. tenella and ARTS is not well-understood, present evidencesupports the hypothesis that the scale needs the ant toremove its honeydew secretions, otherwise the scale woulddrown in its own secretions; and most likely to move crawlerswithin and between plants. As ARTS cannot survive withoutA. tenella, management options that disrupt scale-ant associationwould be most effective in controlling damagingscale populations. Such efforts, however, require solidand sufficient understanding of the biology and ecology ofA. tenella and its impact on ARTS life cycle and ecology.We will first determine the effect of habitat characteristics(e.g., vegetation, temperature, humidity, rainfall, co-occurringant diversity, abundance of ARTS and other ant-tendedhomopteran insects) on patterns of A. tenella distributionand abundance in Southern Cameroon, where ARTS distributionis well known. Secondly, we will determine the level andnature of interactions between A. tenella and co-occurringant species, assess their impact on ARTS development andsurvivorship, and conduct farmer-participatory trials toevaluate the effects of ant exclusion on ARTS abundance anddamage severity on cassava. In a third component, we willdetermine the role of A. tenella workers and queens in ARTSdispersal.Findings from this project will feed into IITA’s cassava, IPM andbiodiversity projects, and the biogeography programmes ofthe University of Basel, with the broad aim of developing sustainablepractices to reduce ARTS infestation on cassava, anddocumenting and conserving biodiversity in Central Africa.Cassava cutting infested with Stictococcus vayssierei57