番茄晚疫病孢囊侵染几率及病害显症模式的研究

 对番茄晚疫病病菌孢囊侵染几率及病害显症进行定量研究,结果表明:孢子囊侵染温限为7-33℃;侵染最低露时为3小时;侵染的最适露温、露时组合为17℃×24hr。以露温、露时及其互作项为自变量,侵染几率为因变量通过逐步回归建立了回归方程。累积显症率随病原菌潜育累积有效积温呈Richards模式增长,显症的潜育累积有效积温范围为66.265-103.18日·度。

PRELIMINARY STUDIES ON THE SPORANGIA INFECTION PROBABILITY AND PATTERNS OF LESION APPEARANCE OF TOMATO LATE BLIGHT (PHYTOPHTHORA INFESTANS)

The quantitative studies on the sporangia infection probability and patt-terns of lesion appearance of Tomato Late Blight (Phytophthora infesians(Mont) de Bary) revealed that the temperature range of sporangia infection was 7 to 33℃.Under the same DT(Dew Temperature),IP (Infection Proba-bility) increased with increasing DP (Dew Period),under the same DP,at first,IP increased with increasing DT,then decreased with increasing DT ranging from 7 to 33℃.The minimum DP for sporangia infection was 3hours.The optimal combination of DT and DP for IP was DT 17℃ X DP 24 hr. Infection probability was a function of DT and DP: IP=-0.78469-0.17962*DP+0.05693*DT*DP-1.34744E-03*DT²*DP -4.7973E-04*DT*DP² The latent period was about 3 days under our experimental conditions in 1987.The daily rate of lesion app earance decreased with time from the first day to the third day.On the first day,the daily rate of lesion appear-ance was maximum,about 60 percent.The Richards model was used todescribe the daily cumulative rate of lesion appearance (CROA): CROA=(1+5.465E+35*EXP(-0.9272*TT))**(-1.0/47.09) TT--accumulated degree days 66.265<=TT<=103.18.