Commercial fungicides in the control of fuzzy mildew (Pseudoperonospora cubensis) in cucumbers (Cucumis sativus), Manabí, Ecuador

Abstract

Cucumber is a cucurbitaceae in high demand worldwide, recognized for its nutritional value and characteristics for fresh consumption; however, its production has been affected by fungal diseases such as downy mildew (Pesudoperonospora cubensis). The objective of this study was to evaluate the efficacy of four fungicides (Metalaxyl+copper oxychloride, Mancozeb+metalaxyl, Fosetyl aluminum, Dimetomorph) in controlling downy mildew in cucumber crops. The research was carried out on plots (20 m²) at the Polytechnic Campus of the Manabí Higher Polytechnic School of Agriculture “MFL”, Manabí, Ecuador; using a completely randomized block design with four replicates. The evaluated fungicides were applied 28, 43, 58 days after sowing (dds). Three evaluations (30, 45, and 60 dds) were carried out to determine the incidence and severity of the disease. The variables evaluated were number of fruits per plant; length, diameter, and weight of the fruits. The incidence assessment at 30, 45 and 60 days did not present statistical differences (100%), however, the severity did present highly statistically significant differences in all treatments (p = 0.0001). The fungicides Metalaxyl + copper oxychloride (36%), Mancozeb + metalaxyl (16.5%), fosetyl-al (42%) and Dimethomorph (24.5%) were effective. Downy mildew severity levels decreased in all three monitoring sessions. Furthermore, Dimethomorph was the phytosanitary product that most significantly increased production variables. These results demonstrated the effectiveness of the rational use of fungicides to control downy mildew and of dimethomorph to increase cucumber crop productivity.