Assessment of Downy Mildew (Pseudoperonospora cubensis) Control in Cucumber (Cucumis sativus) Using Image Processing under Silicon (SiO2) Application

Abstract

The objective of this research was to evaluate the effect of the application of silicon (SiO2) on the control of downy mildew (Pseudoperonospora cubensis) in cucumber (Cucumis sativus) crops. The location of the research was carried out at the “La María” Experimental Farm belonging to the State Technical University of Quevedo (UTEQ), located on the Quevedo-El Empalme road at km 7 of the Province of Los Ríos for two years. The fertilizer that was applied was silicon oxide (SiO2 at 32%), in different doses applied at 8, 23 and 40 days after sowing. A completely randomized block design (DBCA) was used, with six treatments and three repetitions per treatment. The variables that were evaluated were the severity of the downy mildew disease in different treatments and leaves of different heights using a visual evaluation scale and image processing. Some variables of agronomic interest and a benefit/cost type economic analysis were evaluated. To validate the image processing, a linear correlation with a visual scale was used and the rest of the variables were subjected to analysis of variance (Tukey p<0.05) to determine statistical differences. The results obtained show a positive correlation (R2: 0.98) of the Leaf Doctor program with the visual evaluation. The severity of downy mildew did not present differences between the treatments, but the greatest impact was on the lower leaves. Silicon presented positive effects on the different agronomic variables, but only the yield, diameter, length, and average weight of the fruit were higher at doses of 150 ppm of silicon. However, the 125-ppm dose is more profitable as it has no statistical differences with the 150-ppm dose.