Effect of the application of silicon in the control of Phytophthora capsici in bell pepper (Capsicum annuum) using image processing software

Abstract

Phytophtora blight caused by Phytophtora capsici is one of the most important diseases of pepper (Capsicum annuum L.). It infects pepper plants at all growth stages. It can cause seedling death, root rot, crown rot, stem blight, leaf spot, and fruit rot. Assessment of the disease is usually made by visual scale diseases which do not include bell pepper fruits. This evaluation tends to be biased when different control methods are investigated. One method appears to be the utilization of silicon. Silicon thickens plant cell wall reducing disease progression. The experiment was conducted under field and greenhouse conditions for two years at the Universidad Técnica Estatal de Quevedo/Ecuador. Different doses of silicon were evaluated to determine which one had the greatest control of the disease. The evaluation of the disease included visual scales and image processing software. Leaves and fruits were evaluated. The program appears to be suitable for its implementation by linear correlation analysis (R2: 0.90-0.97) compared to the visual disease scales. None of the silicon doses reduced the severity of P. capsici. Other agronomic variables like yield, plant height, number of flowers showed statistical differences through the analysis of variance (Tukey p <0.05) compared to the control. The economic analysis did not recommend the use of silicon in field conditions. The dose of 200 kg/ha of silicon had an increase of 29% of benefit compared to the control under greenhouse conditions.