Some results on the epidemiology of Sclerotinia sclerotiorum causing stalk rot of oil seed rape
1987
Krueger, W. (Biologische Bundesanstalt fuer Land- und Forstwirtschaft, Braunschweig (Germany, F.R.). Inst. fuer Pflanzenschutz in Ackerbau und Gruenland)
The speed of development of apothecia of Sclerotinia sclerotiorum (Lib.) de Bary was dependent on the time of appearance. Early formed apothecia needed some more time to reach their maximum size. The growth rate per day was higher in the first days (0,6 mm/day) than later (0.3 tk 0,1 mm). The spore flight of the fungus took place during and after rains, but only when the rainfall was not too heavy. Two early rain periods in the beginning of May 1985 did not seem to have initiated infection, due to the fact that no or only very slight petal falling was present at that time. The infection of rape seems to be not so much dependent on the numbers of spores present in the air, but more on the microclimate present when spores are discharged, as can be followed from dew measurements. Yield, 1000 kernel weight and the number of bursted pods were more reduced on early infected plants than on those infected later after flowering. There seem to be some differences between cultivars, epecially with respect to pod bursting. More data are necessary. It was tried to find a correlation between the degree of infestation of a field and the number of sclerotia recovered from the soil by washing soil samples. Only very few sclerotia were found in both, the heavy infected fields and in those with only a few plants diseased
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