2022 journal article

Duration of Downy Mildew Control Achieved with Fungicides on Cucumber Under Florida Field Conditions

Plant Disease, 106(4), 1167–1174.

By: A. Shirley*, G. Vallad*, N. Dufault*, R. Raid* & L. Quesada-Ocampo n

author keywords: cucumber; oomycetes; Pseudoperonospora cubensis; vegetables
MeSH headings : Cucumis sativus; Florida; Fungicides, Industrial / pharmacology; Oomycetes; Peronospora; Plant Diseases / prevention & control
TL;DR: Evaluating the field activity of eleven currently utilized fungicides was established by determining their duration of activity when applied at various intervals for the management of CDM in cucumber under Florida field conditions to potentially improve the development ofCDM management programs and slow resistance selection. (via Semantic Scholar)
Source: ORCID
Added: March 30, 2022

Cucurbit production in Florida is impacted by downy mildew on a yearly basis. Cucurbit downy mildew (CDM), caused by Pseudoperonospora cubensis, is one of the most devastating cucurbit diseases and can lead to complete yield loss. Nearly continuous production of cucurbits occurs temporally throughout Florida, which puts extensive pressure on the pathogen population to select for individuals that are resistant to fungicides in use labeled for CDM. Loss of efficacy as a result of fungicide resistance developing is becoming a major concern for Florida cucurbit growers who rely on these products to manage CDM. This study was established to evaluate the field activity of 11 utilized fungicides by determining their duration of activity when applied at various intervals for the management of CDM in cucumber under Florida field conditions. By comparing levels of percent CDM control and area under the disease progress curve values, the fungicide’s duration of field activity was established. Field activities were <1 week for dimethomorph and fluopicolide; 1 week for cymoxanil; 1 to 2 weeks for chlorothalonil and mancozeb; 2 weeks for ethaboxam; 1 to 3 weeks for propamocarb, cyazofamid, and ametoctradin + dimethomorph; and 2 to 4 weeks for oxathiapiprolin and fluazinam. Knowledge of duration of field activity can potentially improve the development of CDM management programs and slow the resistance selection.