Albugo candida causes white blisters or white rust of crucifers is a/an

Albugo candida causes white blisters or white rust on crucifers and is an Obligate parasite.
A.candida is an obligate plant pathogen that infects Brassicaceae species and causes the disease known as white rust or white blister rust. It has a relatively smaller genome than other oomycetes.
This pathogen infects plants in the family Brassicaceae; the growth stages involved include the seedling stage, the growing stage, the flowering stage and the fruiting stage.