Predicting climate-change-caused changes in global temperature on potato tuber moth Phthorimaea operculella (Zeller) distribution and abundance using phenology modeling and GIS mapping

Abstract

Originating from the Andean region and co-evolved with its food plant, the potato (Solanum sp.), the potato tuber moth Phthorimaea operculella (Zeller) has become an invasive potato pest globally. The hypothesis of our present study was that the future distribution and abundance (damage potential) of this pest will be greatly affected by climate-change-caused changes in temperature. We used a process-based climatic phenology model for P. operculella and applied three risk indices (establishment-, generation, and activity index) in a geographic information system (GIS) environment to map and quantify changes for climate change scenarios of the year 2050 based on downscaled climate-change data of the scenario A1B from the WorldClim database. All applications and simulations were made using the Insect Life Cycle Modeling (ILCYM) software recently developed by The International Potato Center, Lima, Peru. The study concludes that there are three possible main scenarios of changes that may simultaneously occur: (1) the P. operculella damage potential will progressively increase in all regions where the pest already prevails today with an excessive increase in warmer cropping regions of the tropics and subtropics. In regions where P. operculella is established and develops >4 generations per year, economic losses are likely to occur; under the current climate, >4 generations are developed on 30.1% of the total potato production area worldwide, which will increase until the year 2050 to 42.4%, equal to an increase of 2,409,974ha of potato under new infestation. (2) A range expansion in temperate regions of the northern hemisphere with additionally 8.6% (699,680ha), 4.2% (32,873ha), and 2.7% (234,404ha) of the potato production area under higher risk in Asia, North America, and Europe, with moderate increases of its damage potential. (3) A range expansion in tropical temperate mountainous regions with a moderate increase of its damage potential; e.g., in Bolivia, Ecuador and Peru 44,281ha, 9569ha, and 39,646ha of potato will be under new risk of infestation. The ILCYM software allowed a detailed analysis of possible climate-change-induced changes in temperature on P. operculella distribution and damage potential. Further, this tool offers means of overcoming limitations in predictions and mapping experienced with climate data interpolation and resolution by spatial point-by-point simulations at locations of interest. The methodology is proposed as a very helpful tool for adaptation planning in integrated pest management.