Trial to control of Japanese oak wilt using decoy tree and aggregation pheromone of Platypus quercivorus (Coleoptera: Platypodidae)

The mass mortality of oak trees (Japanese oak wilt) has recently increased explosively in Japan. Tree mortality is caused by mass attack of the ambrosia beetle Platypus quercivorus, which vectors the pathogenic fungus, Raffaelea quercivora, responsible for Japanese oak wilt. Although a component of the aggregation pheromone of P. quercivorus has been identified as (1S, 4R)-p-menth-2-en-1-ol (quercivorol), several types of traps baited with synthetic quercivorol failed to capture large numbers of beetles, probably because of unsolved problems such as the effectiveness of the synthetic pheromone as an attractant, the release rate, method of release, or purity of the pheromone, or missing pheromone miner components or missing synergistic pheromone components. Thus, we developed a “decoy tree” method, which uses live oak trees inoculated with a fungicide in combination with the synthetic pheromone as a novel and effective method to attract and kill the beetle (patent pending). Field tests showed that decoy trees attracted many P. quercivorus, beetles and that decoy trees possibly survived the infestations in the absence of fungal development.