Previous View
 
APSnet Home
 
Phytopathology Home


VIEW ARTICLE

Ecology and Epidemiology

Weather and Epidemics of Septoria Leaf Blotch of Wheat. Gregory Shaner, Associate Professor, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907; Robert E. Finney, Research Associate, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907. Phytopathology 66:781-785. Accepted for publication 8 January 1976. DOI: 10.1094/Phyto-66-781.

Weather records were compared with severity of Septoria leaf blotch of wheat over a 20-year period at Lafayette, Indiana. In 3 years of “very severe” epidemics, in which all leaves of susceptible cultivars were killed prematurely, there were at least 40 days of rain from 1 April - 17 June, 8 days above average. A “severe” epidemic occurred when there were 34 days of rain if there was no excess of 2-day periods with minimum temperatures of 7 C or lower (34 such periods compared to an average of 26). It may be possible to forecast a “very severe” epidemic at the time flag leaves emerge by examining weather data from the previous 40 days (1 April - 10 May) and predicting weather for the next 35 days. A severe epidemic is likely to develop if past weather has been favorable, if the pathogen is well-established, and if the 30-day outlook is for much above-normal precipitation (17 or more days of rain from 11 May - 14 June).

Additional keywords: Septoria tritici, Triticum aestivum, epidemiology, temperature, moisture.