The effect of Trichoderma longibrachiatum Against Damping-off Pathogens on Different Varieties of Cucumber in Vitro

The study was carried out to evaluate the effect of Trichoderma longibrachiatum against damping-off pathogens on four commercial cultivars cucumber in vitro. Various sites Najaf province including (Abasia, Quzwenia, Haydaria, Manathera and Meshkab) were surveyed detect spread studied disease. Pathogenic fungi isolated from roots stem parts infected plants that collected then diagnosed morphologically. pathogenicity test conducted fungal isolates susceptibility different varieties (Superina F1, Beit alpha Cucumber short Hybrid cucumber) these tested laboratory with presence bio-control T. longibrachiatum. One isolate Fusarium sp. another R. solani found be very virulence which increase percentage damping off seedlings up 90and 100% respectively compare control treatment recorded 100, 95, 90 85 reduced vegetative root growth indicators (the weight length plumule, radicale) chosen complete later studies. diagnosis two confirmed by (PCR) F. as both registered National Center for Biotechnology Information (NCBI) under ON394603 ON398997 accession numbers respectively. Results showed increased when it added alone or other treatments soil plastic pots provided a protection infection F1 more susceptible moderate cucumber, while Superina less clearly indicated plants.