EFFICIENCY OF PAECILOMYCES LILACINUS AS BIOCONTROL AGENT OF CUCUMBER DAMPING OFF DISEASE CAUSED BY PYTHIUM APHANIDERMATUM .

The results of the inhibition activity of culture filtrate of six isolates of Paecilomyces lilacinus grown on potato extracts sucrose broth (PSB) and soybean extract sucrose broth(SSB)against Pythium aphanidermatum , showed that the isolates PL3 and PL4 were the superior in reducing radial growth rate of P. aphanidermatum which recorded 1.83 , 2.16 cm and 0.93 , 0.93 cm for the culture filtrate of PSB and SSB respectively , Greenhouse result revealed that isolates PL3 and PL4 were the best in increasing the most growth parameters ( shoot and root length, no. of leaves and flowers / plant , dry and soft weight of shoot and root/plant) which recorded (30.33 , 27.0) cm ,(13.0 , 12.0) cm , (6.33 , 5.33) leaf/plant, (1.66 ,1.66 ) flower / plant, (1.40 ,1.43) gm/plant, (0.61, 0.63) gm/plant respectively, while the pathogen treatment recorded ( 3.66 , 2.33 ) cm , 1.33 leaf / plant, 0.0 flower/ plant, (0.55, 0.12) gm / plant . Also, greenhouse result showed that isolate PL3 was the more efficient in reducing the disease incidence to 6.66 %. Field experiment showed that isolates PL3 and PL4 significantly reduced disease incidence to 18.66 and 21.66 %. isolate PL3 significantly superior than the fungicide Ridomil in reducing cucumber disease incidence 23.16 % .