NAPPFAST : An internet system for the weather-based mapping of plant pathogens

In recent years, the number of exotic pest introductions has increased rapidly as a result of increased volume of trade (22). The serious and sometimes irreparable ecological and economic damage of exotic pathogens, such as Cryphonectria parasitica, Ophiostoma novo-ulmi, and Phytophthora ramorum, the causal agents of chestnut blight, Dutch elm disease, and Sudden Oak Death, respectively, are amply documented (1,6,42). An estimate of annual losses for exotic plant pathogens is $21 billion dollars (32). The Plant Protection and Quarantine (PPQ) (Sidebar 1) division within the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) has the goal of safeguarding agriculture and natural resources from the risks associated with the entry, establishment, and spread of exotic pathogens. Two important components of the APHIS-PPQ mission are risk analysis and pest detection. A key goal of the risk analysis program is to identify exotic pest pathways and to assess the risks these exotic pests pose to plants and plant products as well as to the environment. Three types of risk assessments that evaluate the probability of the introduction and establishment of exotic plant pests are pathway analysis, organism pest risk assessment, and commodity risk assessment. The PPQ pest detection program and its state cooperators provide a continuum of pest surveillance, from offshore preclearance programs through port inspections, to surveys in rural and urban sites across the United States. The Center for Plant Health Science and Technology (CPHST) and the Cooperative Agricultural Pest Survey (CAPS) programs are instrumental in APHIS-PPQ’s pest detection programs. CAPS is responsible for supplying a means of detection, documentation, and rapid dissemination of information regarding the survey of regulated significant plant pests and weeds in the United States. The survey information gathered by CAPS is entered into a central database known as National Agricultural Pest Information System (NAPIS). CPHST, headquartered in Raleigh, NC, is a multi-program scientific support organization for PPQ. One way CPHST scientists help facilitate the APHIS-PPQ activities of risk analysis and pest detection is by mapping the potential introduction and establishment of exotic pathogens in the United States. These maps are the result of pathogen-specific information analyses, including climate, pathogen distribution, host distribution, and trade. Given its influence on pest phenology, reproduction, dispersion, and overwintering survival, climate is a critical component for the geographic assessment of potential pathogen distribution. A large number of climate-based risk mapping systems, such as CLIMEX, BIOCLIM, and GARP, have been used for pest risk analysis (3,10,38,44). Literature typically focuses on the development and/or evaluation of the best modeling techniques (10); however, often the quality of the inputs, including biological parameters, weather