INTEGRATED PROTECTION FROM PREVALENT WHEAT PARASITES IN SEMIARID REGION

This paper is aimed at presenting contemporary knowledge in the field ofintegral wheat protection against parasites, i.e. the use of cultural measures andgenetic analyses directed at adequate use of breeding results, monitoring andforecasting of prevalent parasite growth and development with the aim of rationalfungicide application. in addition, the paper suggests the proper use of biologicalmeasures through artificial infection with pyrenophora tritici repentis (ptr) in yearsnot favourable for facultative parasite development. growing of the varieties notlower than 85 cm with optimal stem growth ratio in regions with 550–650 mmprecipitation, deep and complete soil cultivation plus nutrition before sowing inlate october reduced the risk of facultative parasite appearance on lower andmiddle leaves by over 15%, which was considered useful because of theantagonism to obligate parasites. severity of puccinia triticina on last two leaveswhen facultative parasites were absent was increased at 60–70% as maximal levelaccording to suggested sagr. nevertheless, we suggest growing of varieties withprolonged latency period resistant to puccinia triticina. the aim is to avoid overaccumulationof resistance genes consequential through the decrease of wheat grainyielding potential. genes facilitating toxin from ptr spreading have to be excludedbecause of necessary antagonistic effect from the middle leaves. this implies genefor the obligate parasite specific resistance diversity of varieties in order to reducethe probability of simultaneous overcoming of resistance and avoid insurmountablechanges in seed production. the final result of the proposed system should be thelast two leaves with mostly minimal parasite appearance and the possibility ofeconomical and efficient single curative treatment application once in ten yearswhen facultative parasites are absent in spring or after the resistance of variety isovercome in standard conditions. the practical aim was also dependent on leaf rustdevelopment and green leaf area dissapearence forecasting models as well asbalance between the size of the farm and equipment due to short deadlines.