| Kingdom: Chromista |
| Phylum: Oomycota |
| Class: Oomycetes |
| Order: Peronosporales |
| Family: Pythiaceae |
| Genus: Phytophthora |
| Subject: Phytophthora spp. De Bary |
| Kingdom: Plantae |
| Phylum: Magnoliophyta |
| Class: Magnoliopsida |
| Subclass: Caryophyllidae |
| Order: Caryophyllales |
| Family: Cactaceae |
| Subfamily: Cactoideae |
| Tribe: Rhipsalideae |
| Genus: Schlumbergera |
| Subject: Schlumbergera truncata (Haw.) Moran |