番茄晚疫病病斑扩展模式的初步研究

PRELIMINARY STUDY ON THE LESION EXPANSION MODEL OF TOMATO LATE BLIGHT(Phytophthora infestans)

对番茄晚疫病病斑扩展过程的定量研究结果表明:病斑潜能传染期为13天,病斑累积扩展面积倍数随病斑扩展累积有效积温呈 Gompertz 模式增长;在病斑潜能传染期内,病斑潜能产孢面积比率随病斑斑龄的增大而逐渐减小,直至为零,两者呈对数关系。

Lesions of tomato late blight are divided into two parts,the cen- tral necrotic area incapable of sporulating and marginal potential sporulative area.When environmental conditions are conducive,the potential sporulative area can Produce sporangia.The Quantitative study on the lesion expansion revealed that the potential infectious period of lesion was 13 days,relative humidity exceeded 90% for sporulation to occur,9.5 hours of relative humidity over 90% were required before sporangia were produced under experimental conditions.The ratio of cumulative lesion expansion area to initial lesion area (CR)was used to describe the lesion expansion rate.Gompertz model was used to describe the relationships between CR and cumulative degree days(TT): CR=40.5077·EXP(-4.6537·EXP(-1.7416E-02.TT)) The ratio of potential sporulative area to the total area of the lesion decreas- ed with increasing lesion ages during the potential infectious period.