Identificación y alternativas de manejo de la cenicilla del rosal

Abstract

Resumen. La cenicilla del rosal causada por Podosphaera pannosa afecta todas las partes aéreas de la planta, lo que repercute en su calidad como principal componente de la pérdida económica. En el presente trabajo, se confirmó la identidad del agente causal de la cenicilla en rosa y se evaluó el efecto del fosfito de potasio (K 3 PO 3 ), silicio, quitosano y acetato de dodemorf sobre la incidencia y severidad de la enfermedad, así como, su respuesta en la calidad de tallos florales. Se realizaron dos ensayos (febrero-abril y mayo-julio). Las caracterís-ticas morfométricas y moleculares del agente causal de la cenicilla correspondieron a Podosphaera pannosa. El K 3 PO 3 , silicio y quitosano redujeron Abstract. Rose powdery mildew caused byPodosphaera pannosa affects all aerial parts of the plant, which affects their quality as a major component of economic loss. In this work, the causal agent of powdery mildew of rose was identity and confirmed, the effect of potassium phosphite (K 3 PO 3 ), silicon, chitosan and dodemorph acetate on the incidence and severity of the disease was evaluated, as well as their response in the quality of flower stalks. Two trials (February to April and from May to July) were performed. The morphometric and molecular characteristics of the causal agent corresponded to Podosphaera pannosa. The K 3 PO 3 , silicon and chitosan they reduced incidence and severity compared to the control for both assays, however, only the K 3 PO 3 and silicon, exhibited a control similar to provided by the fungicide dodemorph acetate. The treatment with chitosan increased the length and diameter of the stem and flower bud in contrast to K 3 PO 3 and silicon, but was not significant to the control in both tests. Based on the results, the K 3 PO 3 , silicon and

Potential of Chitosan for the Control of Powdery Mildew (Leveillula taurica (Lév.) Arnaud) in a Jalapeño Pepper (Capsicum annuum L.) Cultivar

“…In addition, Domínguez-Serrano et al [34] report that the application of 0.013% of chitosan for the control of Podosphaera pannosa reduced the incidence of powdery mildew by 60.3% and 63.1%, being more effective than that reported in this study at a similar concentration of chitosan (34.62% control efficacy), possibly because they are two different genera of powdery mildew and therefore have different tolerance to this biopolymer. This is because chitosan is an antitranspirant and is used to protect plants against oxidative stress, stimulating plant growth.…”

“…A completely randomized design with the following seven treatments was used: T1 = 0.0125% chitosan, T2 = 0.0025% chitosan, T3 = 0.05% chitosan, T4 = 0.1% chitosan, T5 = 0.2% chitosan, T6 = tebuconazole 25% (1.8 mL/L water), and T7 = control (water), with four replicates, which were kept in the laboratory at a temperature of 28 • C and a photoperiod of 12:12 light: dark until the end of the experiment. The concentrations of chitosan in the present study ranged from 0.0125 to 0.2%, because in a previous study the application of 0.013% chitosan decreased the incidence of Podosphaera pannosa by 31.2% (February-April) and 19.3% (May-July), and applications of 0.025 to 0.2% reduced the development of powdery mildew in rose by 43.5 to 85.4% [34].…”

“…Three applications of the treatments were carried out with intervals of 5 days between each one, and the percentage of incidence was evaluated by the number of diseased leaves per plant. In addition, the severity of the disease was evaluated 48 h after the last application [34]. The latter was conducted by comparison with the 16-level descriptive evaluation scale and subsequently the control efficacy was evaluated [49].…”