Downy mildew fungi- everything u need to know

Kingdom-Straminophila or Chromista

Phylum-Oomycota

Class-Oomycetes

Order-Peronosporales/Sclerosporales

Family-Peronosporaceae/Sclerosporaceae

• These group of fungi have a well developed mycelium but they are aseptate

• Cell wall is composed of glucon

• Spores are produced by Sporangia borne on sporangiophore

• Oospore is sexual spore , globose , golden color

on the foliage, small yellow spots develop on the upper sides of the leaf while white to bluish-white fluffy growth forms on the underside of the leaf

Classified based on ::

 1.direct/indirect germination of sporangia
 2.branching of sporangia

Indirect germination(via zoospores) is found in --> Basidiophora , Bremia , Bremiella , Pseudoperenospora , Sclerospora , Plasmopara

Direct germination (via oospores) --> Perenospora , Perenosclerospora , Sclerophthora

Basidiophora

Sporangiphore unbranched, basidium like club shaped, which bear sporangia , Sporangia are produced on sterigmata , Sporangia germinate by zoospores.

Downy mildew of grasses -- Basidiophora butleri

Bremia 

Sporangia born on apophyses which is cup like /saucer shaped structure , Sporangia germinate by germtube , Sporangia are oval shaped

Downy mildew of lettuce --  Bremia lattucae

Bremiella 

Sporangiophore is dichotomous , Sporangia born on apophyses which is cup like , Sporangia is pappilate ,

Downy mildew in impatiens -- Bremiella sphaerosperma

Pseudoperenospora

Sporangiophore is dichotomously branched which bear sporangia Sporangia are lemon shaped with distinct papilla

Sporangia germinate by zoospores and germ tube

Downy mildew in cucurbits -- Psuedoperonospora cubensis

Sclerospora 

Sporangiophore is dichotomously branched , Sporangia are lemon shape ,

Downy mildew in Bajra -- Sclerospora graminicola (Bajra)

Plasmopara 

Sporangiophore branching at right angle to main tube , Sporangia germinate by both zoospores and germtube , Sporangia germinate by both zoospores and germtube.

Downy mildew in grapes – Plasmopara viticola

Perenospora

Sporangiphores are dichotomously branched tapering to fine points bears conidia or sporangia

Sporangia are ellipsoidal shape , zoospores are not formed.

Downy mildew of onion – Perenospora parasitica

Peranosclerospora 

Sporangiophore branching and Sclerospora type and germination of sporangia is of like peronospora , Sporangia are spherical without papilla

Downy mildew of Sorghum – Perenosclerospora sorghii

Sclerophthora

Sporangiophores of indeterminate growth , Sporangiophore is dichotomously branched , Sporangia germinate by zoospores

Downy mildew of Sugar cane -- Sclerophthora phillipines