‘Candidatus Liberibacter solanacearum’ detected on tomato crops in Colorado (US)
In 2002, glasshouse tomato growers from Fort Lupton in Colorado (US) noticed symptoms resembling those of ‘psyllid yellows’ caused by Bactericera cockerelli (vector of ‘Ca. Liberibacter solanacearum’ – EPPO Alert List). Symptoms appeared approximately 6 weeks after the first psyllids were observed in the crops. Symptoms usually began with retarded growth, erectness of new growth, chlorosis and purpling of leaves, followed by an overall chlorosis and production of many small, poor-quality fruits. Samples from symptomatic and asymptomatic plants were collected in September and December 2002. These samples have been stored (in RNAlater bottles) for 6 years, and tested later to verify the possible presence of ‘Ca. Liberibacter solanacearum’. Results clearly indicated that the symptoms of psyllid yellows observed in Colorado in 2002 were associated with the presence of ‘Ca. Liberibacter solanacearum’* in glasshouse tomato crops.
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* In their studies McKenzie et al. have used the other name ‘Ca. L. psyllaurous’. It is not entirely clear whether ‘Ca. L. solanacearum’ and ‘Ca. L. psyllaurous’ correspond to the same pathogen, but for simplification the EPPO Secretariat has chosen to consider them as synonymous.
Sources
McKenzie CL, Shatters Jr RG (2009) First report of ‘Candidatus Liberibacter psyllaurous’ associated with psyllid yellows of tomato in Colorado. Plant Disease 93(10), p 1074.