Plant Pathology (2009) 58, 1092-1103

M. Montes-Borrego, B.B. Landa, J.A. Navas-Cortés, F.J. Muñoz-Ledesma and R.M. Jiménez-Díaz (2009)
Role of oospores as primary inoculum for epidemics of downy mildew caused by Peronospora arborescens in opium poppy crops in Spain
Plant Pathology 58 (6), 1092-1103
Abstract: This study investigated the role of Peronospora arborescens oospores as primary inoculum for downy mildew of opium poppy and infection types that they may give rise to in Spain using an integrative experimental approach that combined pathogenicity tests in growth chambers and field microplots, together with molecular detection of P. arborescens infection by specific nested-PCR assays. The results demonstrated that oospores in infested soil or leaf debris were effective inoculum for ingress of the pathogen through underground plant tissues early in poppy seedling growth. This gave rise to systemic infections that reproduced the stunting, chlorotic syndrome frequently observed in affected plants in commercial fields. Additionally, infection of underground tissues of older plants by oospore inoculum could remain asymptomatic. Results also suggested that sporangia formed on infected plants are effective in producing secondary local infections that later may become systemic and either symptomatic or asymptomatic. Finally, and more importantly, those delayed symptomatic or asymptomatic systemic infections, as well as secondary local infections of capsules, can give rise to infected seeds. This research on the biology of P. arborescens on poppy plants and epidemiology of downy mildew may help to develop knowledge-based disease-management strategies of use in the protection of yields of opium poppy crops in Spain and elsewhere.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Rafael M. Jimenez-Diaz, Juan A. Navas-Cortes, Blanca B. Landa

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Peronospora arborescens	Poppy (Papaver somniferum)	Spain (continental)