A threshold-orientated decision model for an epidemic-related control of Septoria nodorum (Berk.) Berk. in wheat
1989
Verreet, J.-A. (Technische Univ. Muenchen (Germany, F.R.). Lehrstuhl fuer Phytopathologie) | Hoffmann, G.M.
Following some basic decriptions of the biology and harmful effects of Septoria nodorum in wheat, beginning and course of infestation in exemplary studies of control plots are characterized by the average number of pycnidia on various leaf insertions in the development stages EC 31 to EC 75, details are given for the location Osterseeon (district Ebersberg, Upper Bavaria) in the years 1986, 1987 and 1988, and differences due to climate conditions are discussed. An average of 1 - 5 pycnidia on certain leaf insertions as regarded a decisive threshold value for the start of control measures. The effects of fungicide applications performed according to the threshold value model or routine measures (EC 59, EC 37) on the development of the inoculum (pycnidia) are quantified, and yield differences are reported. Experiences with threshold-orientated measures on 6 locations in Bavaria in 1986, 1987, and 1988 are summarized, the threshold value model is lelineated with respect for the various development stages. Sampling procedures for diagnosis and morphological criteria for an exact determination of the development stages are described. The model concept is discussed in view of its applicability for experimental, advisory, and practical purposes
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