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• 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.

• 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.