Relationship between the incidence of latent infections caused by Monilinia spp. and the incidence of brown rot of peach fruit: factors affecting latent infection
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Five field experiments were performed in commercial orchards located in Lleida (Spain) over three growing seasons, 2000–2002, in order to estimate the relationship between the incidence of latent infection caused by Monilinia spp. in peaches and the incidence of post-harvest brown rot. No latent infection was recorded at popcorn and the maximum incidence occurred pre-harvest; in some orchards a second peak was detected during the pit hardening period. Monilinia laxa is the most prevalent species isolated from peaches with brown rot. There was a positive correlation between the incidence of latent infection and that of post-harvest brown rot. The average incidence of latent infection during the crop season explained 55% of the total variation in the incidence of post-harvest brown rot. The effect of temperature (T) and duration of wetness (W) on the incidence of latent infection in peach and nectarine orchards was analysed using multiple regression. The regression analysis indicated that T and W jointly explained 83% of the total variation in the incidence of latent infection. The model predicts no latent infections when T < 8°C, and >22 h wetness are required when T = 8°C but only 5 h at 25°C are necessary for latent infection to occur. The incidence of brown rot and latent infection of peaches caused by M. laxa under controlled experimental conditions were also affected by T and W, as well as by fruit maturity and inoculum concentration. Latent infections were produced in fruit when T was not suitable for the development of brown rot symptoms. In these experiments more than 4–5 h of daily wetness were required after embryo growth in fruit sprayed to run-off with an inoculum concentration higher than 104 conidia ml−1 of M. laxa for brown rot and latent infections to develop. The fitted model obtained from the field data was able to predict the observed data obtained under controlled environmental conditions.
KeywordsEpidemiology Disease management M. laxa M. fructigena M. fructicola
We thank Drs. C. Redondo, J. Segarra, and J.L. Alonso for their helpful discussion and critical reading of the manuscript. This study was supported by grants AGL2002-4396-CO2 and RTA2005-00077-CO2 from the Ministry of Science and Education (Spain). I. Gell received a scholarship from INIA (Spain). We thank Y. Herranz, A. Barrionuevo, and M.T. Clemente for their technical support, and the growers for their support and collaboration.
- Byrde, R. J., & Willetts, H. J. (1977). The brown rot fungi of fruit. Their biology and control. Oxford: Pergamon.Google Scholar
- Campbell, C. L., & Madden, L. V. (1990). Introduction to plant disease epidemiology. New York: Wiley-Interscience.Google Scholar
- Edwards, G. R. (1987). Temperature in relation to peach culture in the tropics. Acta Horticulturae, 199, 61–62.Google Scholar
- EPPO. (2007). List of A2 pests regulated as quarantine pests in the EPPO region. OEPP/EPPO from http://www.eppo.org/QUARANTINE/listA2.htm.
- Gupta, Y., & Agarwala, R. K. (1990). Effect of temperature on growth and infection of peach by Monilinia laxa. Plant Disease Research, 6, 76–79.Google Scholar
- Meier, U., Graf, H., Hess, M., Kennel, W., Klose, R., Mappes, D., et al. (1994). Phänologische Entwick-lungsstadien des Kernobstes (Malus domestica Borkh. und Pyrus communis L.), des Steinobstes (Prunus-Arten), der Johannisbeere (Ribes-Arten) und der Erdbeere (Fragaria x ananassa Duch.). Nachrichtenblatt des Deutschen Pflanzenschutzdienstes, 46, 141–153.Google Scholar
- Northover, J., & Cerkauskas, R. F. (1994). Detection and significance of symptomless latent infections of Monilinia fructicola in plums. Canadian Journal of Plant Pathology-Revue Canadienne de Phytopathologie, 16, 30–36.Google Scholar
- Snedecor, G. W., & Cochram, W. G. (1980). Statistical methods (7th ed.). Ames: Iowa State University Press.Google Scholar
- Tamm, L., Minder, C. E., & Fluckiger, W. (1995). Phenological analysis of brown-rot blossom blight of sweet cherry caused by Monilinia laxa. Phytopathology, 85, 401–408.Google Scholar
- Wichink Kruit, R. J., van Pul, W. A. J., Jacobs, A. F. G., & Heusinkveld, B. G. (2004). Comparison between four methods to estimate leaf wetness duration caused by dew on grassland. In D. Spittlehouse & T. Myers (Eds.), 26th Conference on Agricultural and Forest Meteorology (26AG). (10.1). Boston: American Meteorological Society.Google Scholar
- Xu, X. -M., Bertone, C., & Berrie, A. (2007). Effects of wounding, fruit age and wetness duration on the development of cherry brown rot in the UK. Plant Pathology, 56, 114–119.Google Scholar