''Peronospora violacea'' is a floricolous downy mildew which infects plants in the

Caprifoliaceae The Caprifoliaceae or honeysuckle family is a clade of dicotyledonous flowering plants consisting of about 860 species in 33 to 42 genera, with a nearly cosmopolitan distribution. Centres of diversity are found in eastern North America and easte ...

. It has been reported from hosts in the genera ''

Dipsacus ''Dipsacus'' is a genus of flowering plant in the family Caprifoliaceae. The members of this genus are known as teasel, teazel or teazle. The genus includes about 15 species of tall herbaceous biennial plants (rarely short-lived perennial plants ...

'', '' Knautia'', '' Lomelosia'', ''

Scabiosa ''Scabiosa'' is a genus in the honeysuckle family (Caprifoliaceae) of flowering plants. Many of the species in this genus have common names that include the word scabious, but some plants commonly known as scabious are currently classified in re ...

'', and '' Succisa''. It produces conidiophores on the

petals Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''coroll ...

and styles of the host, oospores inside the petal and style tissue, and suppresses the development of the

anthers The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filamen ...

. Infection is systemic, with

hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

produced in the

xylem Xylem is one of the two types of transport tissue (biology), tissue in vascular plants, the other being phloem; both of these are part of the vascular bundle. The basic function of the xylem is to transport water upward from the roots to parts o ...

of the host

rhizomes In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

and stems. In infected plants of '' Succisa pratensis'' the flowers have longer, pinker petals on which the conidophores are produced. However, other authors report that on the same host it causes the host corollas to be brownish and dead-looking.

Gallery

References

{{taxonbar, from=Q127376334 Peronosporales Plant pathogens and diseases