Probability of Attack by Southern Pine Beetle in Relation to Distance from an Attractive Host Tree

The pattern of southern pine beetle (SPB) attack was examined in two infestations in East Texas to determine the probability of host tree attack ( PA ) as a function of distance ( X ) from a recently attacked tree (pheromone source). In an infestation having a low rate of newly attackedtrees per day and only a few pheromone sources occurring simultaneously, distance was a critical factor in determining PA . The probability decreased as In X , and was described by the regression model, PˆA = 0.06757- 0.2583 In X . Distance, however, was less critical in a larger infestation whichhad multiple pheromone sources occurring simultaneously and a high rate of new trees attacked each day. Implications for pheromone control strategies utilizing SPB attractants are discussed. Forest Sci. 24:574-580.