EFFECT OF SOIL MATRIC POTENTIAL ON SHARP EYESPOT IN GERMINATING WHEATFOLLOWING SEED TREATMENT

The influence of soil matric potential on sharp eyespot was examined i n wheat seedlings following seed treatment with the fungicide cyprocon azole. Emergence of wheat was tested at matric potentials between 0 an d -850 hPa in non-infested soil and in soil infested with Rhizoctonia cerealis. Optimal shoot emergence was at -50 and -20 hPa in non-infest ed and infested soil, respectively. Disease severity was strongly affe cted by soil matric potential. It continuously increased as matric pot ential decreased from -5 to -200 hPa. In contrast, optimum growth cond itions for the pathogen was at matric potentials between -50 and -200 hPa. With decreasing matric potential the drought stress for the plant seems to increase its predisposition to the pathogen. Seed treatment with cyproconazole reduced sharp eyespot although disease severity inc reased with decreasing soil matric potential.