Diagnosis the Pseudoperonospora cubensis Causes Downy Mildew in Cucumbers and its Resistance to Potassium Silicate and Extract Eggplant Wild

Abstract

Abstract A field experiment was carried out to test the efficiency of potassium silicate and wild eggplant Solanum eleaegnifolium normal and nano for the management of downy mildew disease on cucumber caused by Pseudoperonospora cubensis under greenhouse conditions by reducing the incidence and severity of the disease and its reflection on the efficiency of the control and the area under the disease progress curve AUDPC compared to the fungicide Energy Previcur (Hcl - Propamocarb and Fosetyl-aluminum). The results of phenotypic and molecular diagnosis using polymerase chain reaction (PCR) technology for the two tested isolates showed that they are Pseudoperonospora cubensis. The nucleotide sequences were deposited in the gene bank under accession numbers ON509850 and ON509851. The results of the field trial indicated that the normal potassium silica at a concentration of 2.5 ml L-1 prevented the disease completely, with a severity rate and infection rate of 0.00%, it gave the highest reduction recorded with significant differences from the control treatment infected with artificial infestation 45.90% and 24.27%, respectively. They are followed by the normal and nano fungicide treatments. With regard to the effect of different treatments on the percentage of control, the results showed that the highest control percentage was recorded in the treatment of normal potassium silicates (100%), followed by the treatment of nano silicates (65.88%). Whereas, treatments of alcoholic and nano eggplant wild extract gave 51.64% and 50.50%, respectively, and 63.04 % and 63.09 % for the normal and nano fungicides, respectively.