Response of cucumber cultivars to target spot based on epidemiological components of the disease monocycle

Abstract

Target spot, caused by Corynespora cassiicola (Berk. & M.A. Curtis) C.T. Wei, has a wide range of hosts including more than 350 mono and dicotyledonous species of plants distributed over several countries with tropical and subtropical climates (Dixon et al., 2009). In recent decades, this disease has become one of the major problems affecting plants from the Cucurbitaceae and Solanaceae families in Brazil (Lopes et al., 2005). Epidemics are frequently reported by cucumber growers, both in greenhouse conditions and in the open field (Bezerra & Bentes, 2015;Martins, 2003;Teramoto et al., 2011).Yield losses of up to 60% have been reported in Japanese cucumber cultivated in greenhouses (Verzignassi et al., 2003). Even for cultivars (cvs.) considered to have some level of resistance, such as Taiko

Cucumber Response to Target Blot as a Result of the Effect of Products on Disease Control

“…A similar result was observed when analyzing the drying of these leaves, with the K phosphite not differing from the inoculated control at 60 days, with more than 75% of dry leaves, and the other products delaying leaf death the same as the non-inoculated control (Figure 1). From 15 days after inoculation of the plants, the non-inoculated plants showed a progressive increase in the disease, resulting in 39.6% of dry leaves (2nd and 3rd true leaves) at 60 days of cultivation, a result of the natural inoculum of the pathogen produced by the inoculated plants, considering that the disease has a latent period of five days in the Soldier cultivar (Fischer et al, 2021b).…”

Survey of cucumber target spot, in vitro sporulation and aggressiveness of Corynespora cassiicola

“…It is noteworthy that the symptoms of the diseases found are similar (Figure 1) and that their identification was only Fischer et al (2022) Survey of cucumber target spot, in vitro... (Fischer et al, 2021). It is noteworthy that in sampling with Safira cv., in a property located in the municipality of Bariri-SP, the target spot was not detected.…”

“…The three isolates considered more aggressive, with 19.0; 20.4 and 22.3% of disease severity, originating, respectively, from Reginópolis, Itápolis and Avaí, were preserved in the Mário Barreto Figueiredo Micoteca, of the APTA, Biological Institute of São Paulo, with the names MMBF 01/20 , 02/20 and 03/20, respectively, and selected for studies to evaluate the behavior of cucumber genotypes in relation to the disease (Fischer et al, 2021).…”

“…Wei. Epidemics of the disease have been reported in the states of Amazonas (Bezerra & Bentes, 2015), Goiás (Teramoto et al, 2011), Paraná (Verzignassi et al, 2003) and São Paulo (Fischer et al, 2021). Yield losses greater than 20% were attributed to the disease (Fischer et al, 2021); however, there is no accurate survey of the prevalence of this disease in cucumber.…”

“…There is no consensus on the most favorable culture medium for pathogen sporulation. Several studies use or advocate the potato-dextrose-agar (PDA) medium in the production of inoculum (Fernando et al, 2012;Mesquini, 2012;Teramoto et al, 2013;Teramoto et al, 2017;Mello et al, 2018), with reports of other culture media considered also favorable, such as V-8 juice (Dixon et al, 2009;Parada et al 2012), Czapek-agar (Melo & Reis, 2010, Mesquini, 2012, potato-sucrose-agar (Sousa & Bentes, 2014), carrot-peadextrose-agar leaves (Fortunato et al, 2015) and tomato juice (Fischer et al, 2021).…”