利用Monte-Carlo模拟再评估梨火疫病病菌随水果果实的入侵风险

以梨火疫病随进境苹果果实传入的可能性为例，利用Monte-Carlo模拟方法评估有害生物的入侵风险。按照4种不同场景分别建立B分布来拟合入境水果中感染梨火疫病的比率，利用Pert分布拟合进口量。模拟表明，在4种场景下，最可能出现病害的时间分别为4702、3458、216和105年，在第4种场景即对入境苹果果实无任何检疫要求的情形下，出现发病的最少年份为14年。结果表明，传入风险随入境数量的增加而增加。

Re-assessment of the probabilities of invasion of the fire blight disease via imported apple fruits using Monte-Carlo simulation

Monte-Carlo simulation was used for the evaluation of the risk probabilities of invasion of the fire blight disease caused by Erwinia amylovora via imported apple fruits by considering that the proportion of infected fruits varying on the production area and the year. Four beta distributions were established to describe the probability distributions of the proportion of infected fruits for 4 different scenarios, respectively. Pert distributions employed for estimation of the numbers of the imported apple fruits. The estimation of the expected invasion time for four scenarios were 4 702, 3 458,216 and 105 years, respectively,and the minimal expected time was 14 years in the fourth scenario, in which described there were no phytosanitary requirements for fire blight. The invasion risk increased with the gain of the imported number.