GIS Applications for Forecasting Spread of Invasive Pest (Bactrocera invadens) in Africa

The NCSU/APHIS Plant Pest Forecast System (NAPPFAST) is an Internet tool for plant pest modeling. It is a joint venture between USDA Animal and Plant Health Inspection Service (APHIS); North Carolina State University (NCSU); and ZedX, Inc. NAPPFAST uses a graphical user interface to link meteorological and geographic databases with templates for biological modeling.

These maps illustrate forecasts of Bactrocera invadens, a new fruit fly that is rapidly spreading throughout central Africa. By using NAPPFAST, high-risk areas were determined based on optimum temperature for another fruit fly, B. dorsalis. These maps indicate probabilities of having maximum temperature and minimum temperature with host species production volume. Studies conducted thus far have determined the optimum temperature for fruit fly species is 29/18ºC (maximum/minimum) on the basis of fecundity. Central Africa has the most suitable conditions for Bactrocera fruit fly development.

A generation map, created in ArcGIS, indicates the potential generations per year for B. invadens. Temperature is an important factor for many organisms where heat is needed for development. By using degree days required for fruit flies and the NAPPFAST system, possible generation numbers were determined. A combination of spread forecast, pest biology, distribution, and importance of agricultural commodities and distribution of wild hosts are major elements in the determination of risk of B. invadens.

Courtesy of Yu Takeuchi, USDA APHIS.