Mo Jianhua, Stevens Mark, Liu De Li, Herron Grant
EH Graham Centre for Agricultural Innovation (New South Wales Department of Primary Industries and Charles Sturt University), Yanco Agricultural Institute, Private Mail Bag, Yanco, New South Wales 2703, Australia.
Environ Entomol. 2009 Dec;38(6):1575-84. doi: 10.1603/022.038.0608.
A temperature-driven process model was developed to describe the seasonal patterns of populations of onion thrips, Thrips tabaci Lindeman, in onions. The model used daily cohorts (individuals of the same developmental stage and daily age) as the population unit. Stage transitions were modeled as a logistic function of accumulated degree-days to account for variability in development rate among individuals. Daily survival was modeled as a logistic function of daily mean temperature. Parameters for development, survival, and fecundity were estimated from published data. A single invasion event was used to initiate the population process, starting at 1-100 d after onion emergence (DAE) for 10-100 d at the daily rate of 0.001-0.9 adults/plant/d. The model was validated against five observed seasonal patterns of onion thrips populations from two unsprayed sites in the Riverina, New South Wales, Australia, during 2003-2006. Performance of the model was measured by a fit index based on the proportion of variations in observed data explained by the model (R (2)) and the differences in total thrips-days between observed and predicted populations. Satisfactory matching between simulated and observed seasonal patterns was obtained within the ranges of invasion parameters tested. Model best-fit was obtained at invasion starting dates of 6-98 DAE with a daily invasion rate of 0.002-0.2 adults/plant/d and an invasion duration of 30-100 d. Under the best-fit invasion scenarios, the model closely reproduced the observed seasonal patterns, explaining 73-95% of variability in adult and larval densities during population increase periods. The results showed that small invasions of adult thrips followed by a gradual population build-up of thrips within onion crops were sufficient to bring about the observed seasonal patterns of onion thrips populations in onion. Implications of the model on timing of chemical controls are discussed.
开发了一个温度驱动的过程模型，以描述洋葱上烟蓟马（Thrips tabaci Lindeman）种群的季节性模式。该模型使用每日同龄群（处于相同发育阶段且日龄相同的个体）作为种群单位。阶段转变被建模为累积度日的逻辑函数，以考虑个体发育速率的变异性。每日存活率被建模为日平均温度的逻辑函数。发育、存活和繁殖力的参数根据已发表的数据进行估计。使用单次入侵事件启动种群过程，从洋葱出苗后1 - 100天（DAE）开始，持续10 - 100天，每天每株的入侵速率为0.001 - 0.9头成虫。该模型针对2003 - 2006年期间澳大利亚新南威尔士州里弗赖纳两个未喷洒农药地点观察到的烟蓟马种群的五种季节性模式进行了验证。模型的性能通过基于模型解释的观测数据变化比例（R²）和观测种群与预测种群之间总蓟马日数差异的拟合指数来衡量。在测试的入侵参数范围内，模拟和观测的季节性模式之间获得了令人满意的匹配。在入侵起始日期为6 - 98 DAE、每日入侵速率为0.002 - 0.2头成虫/株/天且入侵持续时间为30 - 100天的情况下，模型获得了最佳拟合。在最佳拟合入侵情景下，该模型紧密再现了观测到的季节性模式，解释了种群增长期成虫和幼虫密度变异性的73 - 95%。结果表明，少量成年蓟马的入侵，随后洋葱作物内蓟马种群的逐渐增长，足以导致洋葱上烟蓟马种群出现观测到的季节性模式。讨论了该模型对化学防治时机的影响。
