Gilligan C A
Department of Applied Biology, University of Cambridge, Pembroke Street, Cambridge, CB2 3DX.
New Phytol. 1990 Jun;115(2):223-242. doi: 10.1111/j.1469-8137.1990.tb00448.x.
A method of analysis, involving the comparison of parameters of nonlinear models for disease progress, is described. The method tests the effects of measures for disease control on the dynamics of botanical epidemics. It was applied to published disease progress curves for a range of host-pathogen systems and was used to test whether treatments to control disease did so by slowing or delaying the epidemic or by reducing the asymptotic-carrying capacity of the host population. The treatments included genetical, chemical and cultural methods including soil solarization, varietal differences and fungicide application. The logistic model was used to summarize polycyclic epidemics of Phytophthora infestans (Mont.) de Bary on potato, P. cryptogea Pethyb. & LafT. on raspberry, Fusarium oxysporum f. sp. lycopersicae (Sacc.) Snyd. & Hans, on tomato, and Puccinia recondita Rob. on wheat and triticale. The monomolecular model was used for epidemics of Sclerotium rolfsii Sacc. on carrots and S. cepivorum Berk, on garlic, that were experimentally limited to one cycle of infection. The selected model was first fitted separately to the empirical progress curve for each treatment. Subsequently, one or more common parameters were constrained to fit all treatments while the remaining parameters were separately fitted. Comparison of the changes in residual mean squares permitted approximate tests for the effects of fitting common parameters. The biological meaning of the parameters is discussed in relation to disease control. The method was sensitive in demonstrating differences amongst the treatments. Marked differences in epidemics were shown to occur when control of disease was effected by reduction in the carrying capacity or by delaying the onset of an epidemic. Few treatments, however, affected the rate parameters, especially of the logistic model.
本文描述了一种分析方法，该方法涉及比较疾病进展的非线性模型参数。此方法用于测试疾病控制措施对植物病害流行动态的影响。它被应用于一系列宿主 - 病原体系统已发表的疾病进展曲线，并用于检验控制疾病的处理措施是通过减缓或延迟病害流行，还是通过降低宿主种群的渐近承载能力来实现的。这些处理措施包括遗传、化学和栽培方法，如土壤太阳能消毒、品种差异和杀菌剂应用。逻辑斯蒂模型用于总结致病疫霉（Mont.）de Bary在马铃薯上、隐地疫霉Pethyb. & LafT.在悬钩子上、尖孢镰刀菌番茄专化型（Sacc.）Snyd. & Hans在番茄上以及隐匿柄锈菌Rob.在小麦和小黑麦上的多循环病害流行情况。单分子模型用于胡萝卜上齐整小核菌Sacc.和大蒜上洋葱核盘菌Berk的病害流行情况，这些病害在实验中被限制在一个感染周期。首先将选定的模型分别拟合到每种处理的经验进展曲线上。随后，约束一个或多个公共参数以拟合所有处理，而其余参数则分别拟合。通过比较剩余均方的变化，可以对拟合公共参数的效果进行近似检验。文中还讨论了参数与疾病控制相关的生物学意义。该方法在显示处理措施之间的差异方面很敏感。结果表明，当通过降低承载能力或延迟病害流行的开始来控制疾病时，病害流行会出现显著差异。然而，很少有处理措施会影响速率参数，尤其是逻辑斯蒂模型的速率参数。
