The apple snail, Pomacea canaliculata: an evidence note on invasiveness and potential economic impacts for East Africa

................................................................................................................................ 3 Executive summary ............................................................................................................... 4 Acronyms and abbreviations ................................................................................................. 9 Introduction ......................................................................................................................... 10 1 Rice cultivation and the apple snail problem..................................................................... 11 1.1 History of rice production and trends in Africa ....................................................... 11 1.2 Biology and identification of invasive Pomacea species ........................................ 14 1.3 Invasive apple snail spread around the world ........................................................ 16 1.4 Invasive apple snail host range and general impacts ............................................. 18 1.5 Invasive apple snail impact on human health ........................................................ 20 1.6 Current spread and distribution of invasive apple snail in Africa ............................ 21 1.7 Modelling the distribution of invasive apple snail ................................................... 23 1.8 Environmental suitability for invasive apple snail colonization ................................ 25 2 Impacts of apple snail on rice and other socio-economic variables .................................. 26 2.1 Documented global impacts .................................................................................. 26 2.2 Prediction of economic and yield loss due to invasive apple snail in East Africa .... 28 2.3 Potential impacts of invasive apple snail on trade .................................................. 33 3 Control methods ............................................................................................................... 33 3.1 Chemical control .................................................................................................... 34 3.2 Microbial pesticides ............................................................................................... 36 3.3 Botanicals .............................................................................................................. 36 3.4 Resistant varieties ................................................................................................. 37 3.5 Biological control ................................................................................................... 37 3.6 Good agricultural practice ...................................................................................... 39 3.7 Integrated pest management (IPM) ....................................................................... 41 4 Advice, information and communication ........................................................................... 51 4.1 Sources of information on apple snail control ........................................................ 51 4.2 Criteria for control advice ....................................................................................... 51 4.3 Information resources and tools ............................................................................ 52 5 Recommendations ........................................................................................................... 53 Acknowledgements ............................................................................................................. 55 References ......................................................................................................................... 56