Effect of greenhouse dehumidification on damages caused by Botrytis cinerea to poinsettia
Rizzo, D.; Burchi, G.; Stefani, L.; Antonetti, M.; Haegi, A.; Teani, A.; Grassotti, A.
Journal of Plant Pathology
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This work is carried out for a Research Project, funded by Mi.P.A.A.F., that studies application of air dehumidification by means of hygroscopic solutions for humidity and climate control and energetic management in greenhouses floriculture. Phytosanitary surveys were performed in two greenhouses in Verdello (Bergamo, in the North of Italy), one containing the dehumidification system and the other one utilised as a control, with the aim to evaluate beneficial effects of dehumidification on phytosanitary control. Analyses were performed on Euphorbia pulcherrima pot-plants cultivated in both greenhouses from October to December 2010. Damages on several plants, with symptoms of vegetative wilt that finally led to plant death, were recorded. Eighty percent of symptomatic plants belonged to the ‘control’ greenhouse (without dehumidification system). Symptomatic samples (27) were collected to study etiology of the disease: visual observation and mycological isolations revealed the presence of Botrytis cinerea and other saprophytic fungi. To confirm these results, molecular protocols were optimized to screen for ITS4/6 (PCR end point), Thielaviopsis basicola (PCR Real Time_taqman), Phytophthora spp (PCR end point) and Botrytis cinerea (PCR Real Time_SybrGreen). Results on 27 symptomatic samples showed that 100% (27/27) were positive for Botrytis cinerea, 92.6% (25/27) amplified with ITS4/6 (that amplify oomycetes), 7.4% (2/27) were positive for Phytophthora spp. and no one was positive for Thielaviopsis basicola. Results show that in these environmental conditions (greenhouse) the main pathogen of Poinsettia seedlings is Botrytis cinerea and that dehumidification of the environment can better control the pathogen