التشخيص الجزيئي لفيروس موزاييك الخيار و مكافحته أحيائيا بالطحلب Spirolina platensis ولبكتيريا Pseudomonas fluorescens و بعض مستخلصات النباتات الطبية تحت ظروف الزراعة المكشوفة

This work was conducted in Al-Ehwaish Area, Samarra District, Salahaddin Governorate during autumn of 2017-2018 growing season. The study aimed at diagnosing the local CMV isolate (Cucumber mosaic virus, genus Cucumovirus, family Bromoviridae) and evaluating the effect of the disease on three cucumber varieties following different biological control approaches. The use of RT-PCR (Reverse transcription-polymerase chain reaction) confirmed that the virus strain used in this study was Cucumber mosaic virus (CMV), and was very close to a Pakistani isolate of the same virus. The efficacy of three plant extracts of Albizia lebbeck (L.), licorice (Glycyrrhiza glabral) and Parkinosonia aculeata (L.), the dietary supplements of the algae Spirulina platensis and the bacterium Pseudomonas fluorescens in controlling CMV were evaluated. The combined treatment of the algae + bacterium was superior and led only to 30% infection and 16.2% disease index compared to 100.00% infection and 14.93% disease index for the control treatment. In addition, the combined algae and bacterium treatment produced the highest chlorophyll content amounted to 31.70 Spad, compared to 11.23 Spad for the control. The combined algae and bacteria treatment increased the leaf surface area of Beit Alfa cucumber variety which reached 30.55 cm2 compared to 22.51 cm2 for the control. The yield experiment showed that the combined S. platensis and P. fluorescens treatment was the best with a yield of 1147.0 g/plant for the cucumber variety Nejm, and the lowest was for the combined treatment of the A. lebbeck and S. platensis extracts with the cucumber variety Ghazir which yielded 420.5 g/plant, whereas the control treatment yield was 390.8 g/plant.