Identification and Fungicide Sensitivity of Colletotrichum spp. from Apple Flowers and Fruitlets in Brazil

Abstract

Glomerella leaf spot (GLS) and bitter rot (BR), caused by Colletotrichum spp., are major diseases on apple in southern Brazil. Among IPM tools for disease management in commercial orchards, fungicides remain an important component. This study aimed to identify Colletotrichum species from cultivar Eva in Paraná state orchards, evaluate their in vitro sensitivity to cyprodinil, tebuconazole, iprodione, and fluazinam, and determine the baseline in vitro sensitivity of these isolates to benzovindiflupyr and natamycin. Most isolates belonged to C. melonis and C. nymphaeae of the C. acutatum species complex. The two species varied in sensitivity to fluazinam and tebuconazole, but no variability was found for any other fungicide. The lowest EC50 values of Colletotrichum spp. were observed for cyprodinil (mean EC50 < 0.02) and benzovindiflupyr (mean EC50 < 0.05); EC50 values were intermediate for fluazinam (mean EC50 < 0.33) and tebuconazole (mean EC50 < 0.14); and highest for natamycin (mean EC50 < 5.56) and iprodione (mean EC50 > 12). Cyprodinil and fluazinam are registered for use in Brazil for apple disease management but not specifically for GLS and BR. Tebuconazole is one of the few products registered for Colletotrichum spp. control in apples. As conclusion, flowers and fruitlets can serve as sources of inoculum for GLS and BR disease; C. acutatum was the predominant species complex in these tissues; cyprodinil and fluazinam applications may suppress GLS and BR; and benzovindiflupyr and natamycin warrant further investigation for GLS and BR disease control of apple due to comparably high in vitro sensitivity.

Study on the Antifungal Activity and Potential Mechanism of Natamycin against Colletotrichum fructicola

“…Our results showed that natamycin exhibited great inhibition on the mycelia and spores of C. fructicola with a dosedependent mode, and the EC 50 and MIC values were only 1.11, 1.28, and 10 mg/L, respectively, which was even lower than that against the mycelial growth of Colletotrichum nymphaeae (5.563 mg/L) and Colletotrichum melonis (5.174 mg/L) reported previously. 17 Moreover, natamycin also displayed both protective and curative effects on apple fruit. Natamycin at 800 mg/L could entirely block the expansion of disease spots, which was nearly equal to the efficacy of flusilazole at 400 mg/L, but higher than the concentration of natamycin (200 mg/L) against Botrytis cinerea and Penicillium expansum on grape berries and jujube fruit.…”

“…Our results showed that natamycin exhibited great inhibition on the mycelia and spores of C. fructicola with a dose-dependent mode, and the EC 50 and MIC values were only 1.11, 1.28, and 10 mg/L, respectively, which was even lower than that against the mycelial growth of Colletotrichum nymphaeae (5.563 mg/L) and Colletotrichum melonis (5.174 mg/L) reported previously . Moreover, natamycin also displayed both protective and curative effects on apple fruit.…”

“…7681-93-8, IUPAC name and chemical structure are provided in Supporting Information Figure S1) belongs to the natural products of polyolefin macrolides compounds, which was first isolated from the soil-dwelling bacteria Streptomyces natalensis. It had great and broad-spectrum antifungal activities, such as against Candida, Aspergillus, Colletotrichum, and Penicillium. − Owing to their safety for humans, animals, and the environment and significant effectiveness against food pathogens, it has been widely used in the food industry as an additive for over half a century. Moreover, natamycin was also considered as a biofungicide for the control of postharvest diseases, and the research and application of natamycin in the field of fruit and vegetable preservation have also been reported .…”

Identification and Genetic Diversity Analysis of the Pathogen of Anthracnose of Pepper in Guizhou

“…Most of the above techniques target one or several types of anthrax bacteria. However, the pathogenicity of different strains of pepper and their sensitivity to pesticides are different [ 25 , 26 , 27 , 28 ], which makes it difficult to prevent and control pepper anthracnose.…”

Occurrence characteristics and control measures of plant pests and diseases

“…Good facilities provide a superior environment for flower production, and provide a good breeding and harm environment for the occurrence of diseases and pests [1] . Facilities have broken the unfavorable conditions of pests and diseases over winter and summer, so that pests and diseases have achieved annual reproduction and infestation, which has caused a greater threat to the plant flower production, not only destroying the ornamental value of flowers, but also causing greater economic losses to the producers, which is not conducive to the intensive and large-scale production of flowers [2] . This study analyzed the occurrence characteristics of plant pests and diseases, explored the dominant diseases and pests and their occurrence conditions, and formulated comprehensive prevention and control countermeasures of facility dominant diseases and pests, aiming at providing strong technical support for the healthy development of facility flowers in Hubei Province.…”