CHAETOMIUM SPP COLONIZATION OF BARLEY FOLLOWING SEED TREATMENT AND ITS EFFECT ON PLANT-GROWTH AND ERYSIPHE-GRAMINIS F-SP HORDEI DISEASE SEVERITY

Experiments were carried our to determine the effect of saprophytic fu ngal endophytes (Chaetomium spp.) on barley (cv. 'Tapir') plans growth , bacterial colonization of the rhizosphere and in vitro/in vivo inhib ition of challenged Erysiphe graminis f. sp. hordei. Seed treatments w ith C. globosum and C. funicola resulted in an increase in root fresh weight. Shoot fresh weight was not affected. Total bacterial density ( cfu/g on Tryptic-Soy-Agar) of rhizosphere soil was not altered by the presence of the endophytes. After seed inoculation and 3 weeks of cult ivation, the fungi were re-isolated initially from the roots and later fr om the leaves without causing any symptoms. Frequency of endophyte re-isolation from plant tissue was higher for C.funicola (max. 95 %) than for C. globosum (max. 44 %). The use of sport suspensions for ino culation led to better colonization of the tissues as indicated by the higher re-isolation. rates than alginate pellets. Culture filtrates o f the fungal endophytes inhibited in vitro the germination of mildew c onidia on solid media (max. 41 % reduction). Abnormal morphological st ructures were nor: detected Following exposure to the metabolites. iri vivo experiments tinder greenhouse condition revealed an antagonistic effect of C. globosum on powdery mildew development on primary leaves of barley cv, 'Jana' which is also shown to be colonized by this endo phyte. Reductions in disease severity varied from 16-48 % compared to the untreated control. The potential of saprophytic endophytes for pla nt health purposes is discussed.