Search

Search Results

• Yield loss caused by fruit rot fungi on sweet cherry in Kyustendil region, Bulgaria

  49-52.

  B. Borovinova

  Views:

  150

  The aim of the study was to determine the incidence of fruit rot caused by several fungal pathogens from 1999 to 2003. The study was conducted in three sweet cherry orchards at the Institute of Agriculture (Kyustendil, Bulgaria). One copper containing fungicide was applied in late autumn and early spring. During the growing seasons, 2-5 sprays were applied against fungal diseases. Trees were not sprayed specifically against fruit rot during the growing season, with the exception of 1999, when a spray of myclobutanil was applied after a long rainy period during the maturity of fruits. In one orchard, two nitrogen fertilization treatments were also prepared. In treatment 1, trees were fertilized with ammonium-nitrate 10 g/m² and in the other treatments trees were not. Incidence of the five most important fruit rot pathogens, Monilinia fructigena, M. laxa, Botritys cinerea, Alternaria alternata and Rhizopus stolonifer was assessed in all orchards. The most severe yield loss (14.80 %) was measured in 1999, when weather conditions were the most favourable for fruit rot development. In this year, brown rots (M. fructigena and M. laxa) caused the highest damage (9.22 and 4.04 %, respectively) out of all assessed fruit rot pathogens. In all other years, yield loss was significantly lower than in 1999. In 2002, A. alternata caused the main fruit rot (4.46%) and all other fungi were less important, while in 2003, B. cinerea caused considerable yield loss (2.28 %) compared to all other fruit rot pathogens. Experiments on fertilization showed that nitrogen significantly increased fruit rot damage in 1999, 2001, 2002 and 2003. The effect of nitrogen fertilization was higher in years with rainy periods around harvest (1999 and 2002) compared to more dry years (2000 and 2001). Results were compared with similar studies and biological interpretations of the results are discussed.

• The brown rot fungi of fruit crops (Monilinia spp.): II. Important features of their epidemiology (Review paper)

  17-33.

  I. J. Holb

  Views:

  246

  Plant disease epidemiology provides the key to both a better understanding of the nature of a disease and the most effective approach to disease control. Brown rot fungi (Monilinia spp.) cause mainly fruit rot, blossom blight and stem canker which results in considerable yield losses both in the field and in the storage place. In order to provide a better disease control strategy, all aspects of brown rot fungi epidemiology are discribed and discussed in the second part of this review. The general disease cycle of Monilinia fructigena„M. laxa, M. fructicola and Monilia polystroma is described. After such environmental and biological factors are presented which influence the development of hyphae, mycelium, conidia, stroma and apothecial formation. Factors affecting the ability of brown rot fungi to survive are also demonstrated. Then spatio-temporal dynamics of brown rot fungi are discussed. In the last two parts, the epidemiology of brown rot fungi was related to disease warning models and some aspects of disease management.

• Brown rot blossom blight of pome and stone fruits: symptom, disease cycle, host resistance, and biological control

  15-21.

  I. J. Holb

  Views:

  901

  In this paper, important features of symptoms, biology and biological disease management are summarised for brown rot blossom blight fungi of pome and stone fruit crops (Monilinia laxa, Monilinia fructicola and Monilinia mali). Firstly, European brown rot caused by Monilinia laxa is discussed highlighting the blossom epidemiology features, then host susceptibility of the most important stone fruit species including several Hungarian and international cultivars. At the end of this chapter, recent biological control possibilities against Monilinia laxa are also included. Secondly, American brown rot caused by Monilinia fructicola is discussed. Symptoms, biological features of blossom blight and host susceptibility of flowers to Monilinia fructicola are demonstrated. Finally, the symptoms and the biology of the least frequent species, Monilinia mali are shown.

• The brown rot fungi of fruit crops (Monilinia spp.): I. Important features of their biology (Review paper)

  23-36.

  I. J. Holb

  Views:

  213

  The brown rot fungi of fruit crops (Monilinia spp.): Important features of their biology (Review paper)

• The brown rot fungi of fruit crops (Monilinia spp.): III. Important features of disease management (Review paper)

  31-49.

  I. J. Holb

  Views:

  335

  In the third part of this review, important features of disease management are summarised for brown rot fungi of fruit crops (Monilinia fructigena, Monilinia laxa, Monilinia fructicola and Monilia polystroma). Several methods of brown rot disease management practices were collected and interpreted in five main chapters. In these chapters, details are given about the legislative control measures, the cultural, physical, biological and chemical control methods. Chemical control is divided into two parts: pre-harvest and post-harvest chemical control. In addition, host resistance and fungicide resistance statuses are also included in this part of the review. Finally, future aspects of brown rot disease control are discussed.

• Disease warning models for brown rot fungi of fruit crops

  19-22.

  I. J. Holb

  Views:

  279

  In this review, disease warning models for brown rot fungi, including Monilinia fructigena, M. laxa and M. fructicola, were summarized. Few studies have been made to relate epidemiology and disease warning in brown rot infection caused by M. fructicola and M. laxa in order to predict infections or develop decision support models for fungicide applications during the growing season. More recently a disease warning model and a decision support system were also performed for M. fructigena for organic apple orchards. This review gives an overview on some details of the above disease warning models and decision support system.

• Effect of acidity on growth rate and stroma formation of Monilia fructigena and M. polystroma isolates

  63-67.

  I. J. Holb

  Views:

  197

  The effect of acidity (pH) ranges on the mycelial growth and stroma formation of Monilia fructigena Pers: Fr. and of M. polystroma van Leeuwen was determined on agar plates and apple fruits. Four isolates of each of the brown rot fungi and two apple cultivars, `James Grieve' and 'Cox's Orange Pippin', were used for the study. For the agar plate study, a range of the initial pH was prepared from 2.5 to 6.5. The dishes were inoculated with a 4 mm plug of each isolate and incubated at 23 °C in darkness. The mycelial growth was measured after 1.5, 4, 7, 10 and 20 days of incubation. After a 30-day incubation, stroma formation was determined by image analysis and weighing of mature stroma. In the fruit experiment, both cultivars were inoculated with one isolate of M. fructigena and of M. polystroma. The pH changes were determined after 7, 14, 28 and 35 days of incubation in both healthy and inoculated fruits. The fastest mycelial growth was at pH 4.5 for M. polystroma and at pH 3.5 for M. fructigena. After a 30-day incubation, M. polystroma isolates produced twice or three times more stroma compared to M. fructigena isolates. For both brown rot fungi, the amount of mature stroma increased from pH 3.5 to 5.5, and then decreased at pH 6.5. Results of the.fruit experiment showed that healthy fruits were quite acidic (pH < 3.5), but pH rapidly increased in the inoculated fruits for both cultivars, reaching pH 4.6-5.4 depending on cultivar and fungus isolate. On both cultivars, the stroma developed at a significantly higher pH for M. polystroma than for M. fructigena. Biological and practical implications of the results are discussed.