Peronospora somniferi Voglmayr, 2014

on Papaver

Papaver somniferum, Hungary, Levél © László Érsek

malformed leaves

underside of an infected leaf

The down is exceptionally deeply coloured here.

gall

Infection ultimately systemic, plants then stunted and strongly distorted.
underside of the leaves with a felt-like greyish down of erect conidiophores that apically several times are dichotomously branching, each branch ending upon a > 20 µm conidium. Embedded in the host tissue lie brown, thick-walled, smooth oospores.

host plants

Papaveraceae, narrowly monophagous

Papaver somniferum.

primary and secondary infections.

In situations where poppies are cultivated for a series of years it is possible to distinguish between primary and secondary infections. A primary infection happens when plants already in the seedling stage are infected by oospores that have passed the winter in the soil. The infection then is systemic, the plans are stunted and large-scale malformations occur (pictures above). Secondary infections are caused by airborne conidia; these infections cause localised lesions on the leaves (photos below)

Papaver somniferum, Hungary, Levél © László Érsek

old lesions, upper side

underside

references

Chater, Woods, Stringer, ao (2020a), Jage, Klenke, Kruse ao (2017a), Müller (2015a), Thines & Choi (2016a), Voglmayr, Montes-Borrego & Landa (2014a).