Risk maps of appearance and development of the pine wilt disease (Bursaphelenchus xylophilus) in Extremadura

Abstract

The recent outbreak of the pine wilt disease in Setúbal, caused by Bursaphelenchus xylophilus, has forced Portugal to adopt quarantine measurements in relation to wood exportations. The risk of appearance and development of the disease in Extremadura was evaluated. The specific susceptibility of Pinus spp., the average daily temperatures of July, and the risk of appearance of the nematode from the Portuguese border or from sawmills located in Extremadura were considered. The risk was defined in four classes, which were represented in maps using a GIS. The results showed that almost 70% of the Extremadura pine stands were included within the high (81.043 ha) and very high (27.091 ha) risk classes. This could be explained due to the continued hot temperatures within the region, and due to the presence of the highly susceptible P. pinaster species, occupying about 75% of the pine stands. The main pine stands with very high risk were located at the Herrera del Duque and Puebla de Alcocer regions. The obtained results and the usefulness of the risk maps as tools for disease prevention are discussed.