Latent entry and spread ofColletotrichum acutatum(species complex) in strawberry fields

Abstract

Anthracnose, caused by Colletotrichum acutatum (species complex), has become a troublesome problem in strawberry production worldwide. This paper reports (i) an optimized sampling method combined with a real‐time PCR technique to detect the latent presence of C. acutatum in cold‐stored strawberry plants used as planting material in several European countries, and (ii) a study of the spread of C. acutatum following a point inoculation under field conditions. Screening of different parts of planting material suggested that C. acutatum is most likely to be present on runners and old petioles. In addition, in seven out of nine batches of planting material from different nurseries, latent infection by C. acutatum was detected in at least one of five replicate samples. Field experiments in 2009 and 2010 showed extensive latent within‐field spread of the pathogen on strawberry leaves, with a within‐row dispersal distance up to at least 1·75 m in 1 week. A straw ground cover between the rows did not decrease C. acutatum spread, probably because introduced (and/or subsequent) inoculum was confined to the plant bed (within the row) and was not present between the beds. Moreover, the number of C. acutatum spores on the symptomless leaves, as estimated using a real‐time PCR method, was significantly (P < 0·05) correlated with the incidence of fruit rot at harvest and post‐harvest (r = 0·56–0·66). These results illustrate the importance of detecting latent infections in planting material and strawberry leaves in the field.

Phenotypic Variation of Botrytis cinerea Isolates Is Influenced by Spectral Light Quality

“…Strawberry (Fragaria × ananassa) is an important soft fruit crop that is popular all over the world. Gray mold is a serious disease in strawberry production and leads to important economic losses (Debode et al, 2015;Petrasch et al, 2019). B. cinerea can infect all plant parts of strawberry including leaves, fruits, flowers, petioles, and stems at every growth stage (Williamson et al, 2007;Petrasch et al, 2019).…”

Simultaneous Detection of &lt;i&gt;Colletotrichum acutatum&lt;/i&gt; and &lt;i&gt;C. gloeosporioides&lt;/i&gt; from Quiescently Infected Strawberry Foliage by Real-Time PCR Based on High Resolution Melt Curve Analysis

“…The plausible explanation for differences in detection from different leaf stages receiving same initial inoculum in our study could be due to young stage leaf may not be providing enough nutrients for the growth and development of the fungus and old stage leaf may contain higher concentration of inhibitory metabolites that may interfere with PCR amplification. Debode et al [23] [38] reported a slower establishment of C. acutatum on younger leaves compared to older from the leaf inoculation experiment followed by monitoring through microscopic study and DNA extraction. Similar effects of leaf age on disease development were observed with C. gloeosporioides on leaves of Mulva pusilla [39].…”

Alternative Molecular-Based Diagnostic Methods of Plant Pathogenic Fungi Affecting Berry Crops—A Review

“…The fungus is mainly dispersed by rain, and can enter the host via any plant tissue. Dispersal of conidia can reach as far as 1.75 m through splashing and the infection of one plant in the field by the pathogen proceeds to the whole cultivation [57]. Most frequently C. acutatum infects strawberries through the crown, as there is a humid microclimate [58].…”