Air temperature, rainfalls, air relative humidity, dew, nebulosity and wind are climatic factors that are acting on powdery mildew-wheat tandem. Literature offers pieces of information only for the relationship with temperature and rainfalls. They have proposed a detailed research on mentioned climatic factors on fungus virulence during 2003-2005 with the help of a complete statistic interpretation with the help of SPSS programme. For statistic analysis they have introduced the data of those six climatic parameters and the fungus virulence data on 27 winter wheat varieties cultivated in the experimental plots from S.C.D.A. – Lovrin. Realised researches are allowing studies concerning the elaboration of a prognosis and warning programme for wheat powdery mildew control. They have worked with decade averages for all analysed variables. In model correlation determining they have used the exclusion of analysed factors. There have resulted five regression models that demonstrate the existence of interrelations among studied variables. For all the models the correlation coefficient is greater then 0.7 that shows the existence of interdependence among those analysed variables. Conclusions were next: the greatest influence on the increase of Blumeria graminis f. spec. tritici attack intensity, in conformity with the data obtained after the recording of empiric data is due to the next factors: relative humidity, rainfalls and temperature. The factor that cannot be excluded from the attack intensity analysis and influences conidia dispersal of the fungus is the wind.

Blumeria graminis; temperature; rainfalls; wind; relative humidity; dew; nebulosity; virulence; statistics

Presentation: oral