Pine wilt disease is a lethal tree disease caused by nematodes carried by pine sawyer beetles. Once affected, the trees are destroyed within a few months, resulting in significant environmental and economic losses. The role of asymptomatic carrier trees in the disease dynamics remains unclear. We developed a mathematical model to investigate the effect of asymptomatic carriers on the long-term outcome of the disease. We performed a stability and sensitivity analysis to identify key parameters and used optimal control to examine several intervention options. Our model shows that, with the application of suitable controls, the disease can be eliminated in the vector population and all tree populations except for asymptomatic carriers. Of the possible controls (tree injection, elimination of infected trees, insecticide spraying), we determined that elimination of infected trees is crucial. However, if the costs of insecticide spraying increase, it can be supplemented (although not replaced entirely) by tree injection, so long as some spraying is still undertaken.

松材线虫病是一种致命的树木疾病，由松树甲虫携带的线虫引起。一旦受到影响，树木会在几个月内被摧毁，造成重大的环境和经济损失。无症状携带者树在疾病动态中的作用仍不清楚。我们开发了一个数学模型来研究无症状携带者对疾病长期结果的影响。我们进行了稳定性和敏感性分析来确定关键参数，并使用最优控制来检查几种干预方案。我们的模型表明，通过应用适当的控制，可以消除媒介种群和除无症状携带者之外的所有树木种群中的疾病。在可能的控制措施（树木注射、消除受感染的树木、喷洒杀虫剂）中，我们确定消除受感染的树木至关重要。然而，如果喷洒杀虫剂的成本增加，只要仍然进行一些喷洒，就可以通过树木注射来补充（尽管不能完全取代）。