Pansy mottle syndrome, a disorder of pansies reported since the 1960s, gives rise to various symptoms including leaf distortion, mottling, leaf bleaching, stunting and apical blindness.
Establishing its cause has been complicated by the intermittent nature of its occurrence and the difficulty of associating cause and effect. This project, to see how incidence is affected by environmental factors, was commissioned after symptoms became more frequent in commercial crops in recent years.
ADAS consultant Jill England collected environmental data from four commercial nurseries between July and October 2013, monitoring 10 pansy batches in all, from seed sowing to marketing. Data loggers mounted in the crop at canopy height measured temperature, humidity and light daily.
Symptoms including leaf variegation and distortion were observed in a single batch at one site. Affected plants had been exposed to lower humidity, measured as vapour pressure deficit, and higher temperatures than those at other sites and had been grown-on in a polythene tunnel rather than a glasshouse, with less precise environmental control.
Leaf distortion without variegation developed in another batch but no link could be made to humidity, temperature or light levels. Monitoring continued into 2014 but the results are yet to be published.
Horticultural Development Company
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