Epidemiological Studies of Brown Rot in Spanish Cherry Orchards in the Jerte Valley.

Inmaculada Larena,Paloma Melgarejo,Maria Villarino,Antonieta De Cal

doi:10.3390/jof7030203

Abstract

Cherry brown rot caused by Monilinia laxa was observed and estimated in organic cherry orchard located in the Jerte Valley between 2013 and 2018 (Cáceres, Spain). Climatic variables were collected from this orchard and also from a nearby weather station. The primary inoculum of the pathogen recorded in March was detected in overwintered mummified fruits, ground mummies, and necrotic twigs and was a function of the average temperature of the previous three months (December, January, and February). The first symptoms of brown rot could be observed on flowers until fruit set in April. The months of March and April were identified as the critical period for cherry brown-rot development. A significant positive correlation was identified between brown rot observed at harvest and the mean number of consecutive days in each fortnight of March and April when the percent relative humidity was above 80%. Brown-rot incidence observed over the 6 years ranged from 0 to 38%. More than 11 days with relative humidity >80% in each fortnight of critical period would mean 100% of cherry brown rot at harvest. A forecasting model could be used to predict brown rot infection in Jerte Valley cherries.

Highlights

April when the percent relative humidity was above 80%
Cherry brown rot is caused by Monilinia laxa (Aderh and Ruhland) Honey and M. fructigena (Pers.) Honey in Jerte Valley in Spain [1], where two infection phases, blossom-blight and fruit-rot phases, can be distinguished [2,3]
Primary inoculum was recorded in March of each year (Figure 2a)

Summary

Introduction

April when the percent relative humidity was above 80%. Brown-rot incidence observed over the 6 years ranged from 0 to 38%. More than 11 days with relative humidity >80% in each fortnight of critical period would mean 100% of cherry brown rot at harvest. A forecasting model could be used to predict brown rot infection in Jerte Valley cherries. Cherry brown rot is caused by Monilinia laxa (Aderh and Ruhland) Honey and M. fructigena (Pers.) Honey in Jerte Valley in Spain [1], where two infection phases, blossom-blight and fruit-rot phases, can be distinguished [2,3]. Fruit blight occurs between the periods of blossom blight and harvest fruit rot and often appears on the same shoots that have previously shown blossom and/or shoot blight, and occurs separately from these symptoms [5]. Fruit-blight incidence was related to blossom blight in spring and fruit rot at harvest. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations

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Conclusion