What is the Difference Between Pythium and Phytophthora?

Pythium and Phytophthora are two genera of parasitic oomycetes that cause root rot in plants. They share some similarities but also have distinct differences. The key differences between Pythium and Phytophthora are:

1. Host specificity: Pythium primarily attacks monocotyledon plants, while Phytophthora attacks dicotyledon plants.
2. Taxonomy: Although both genera have been classified in the same family and order (Pythiaceae and Peronosporales), there have been attempts to separate them, with Pythium placed in the family Pythiaceae and Phytophthora in the family Peronosporaceae of the order Peronosporales.
3. Growth rate: Pythium is a fast-growing eukaryote, while Phytophthora is a slow-growing eukaryote.
4. Host specificity: Pythium is not very host specific, whereas Phytophthora is more host-specific.
5. Zoospore differentiation: The definitive differentiation between the two genera lies in the mode of zoospore differentiation. In Phytophthora species, zoospores are differentiated within the sporangium proper and released in an evanescent vesicle at the sporangial apex. In Pythium species, the protoplast of a sporangium is transferred through an exit tube to a thin vesicle outside the sporangium.

While both Pythium and Phytophthora cause root rot in plants, their mode of zoospore differentiation and host specificity help distinguish them from one another.

Comparative Table: Pythium vs Phytophthora

Pythium and Phytophthora are two genera of parasitic oomycetes that cause root rot in plants. They have some differences in their hosts and growth characteristics. Here is a table comparing the differences between Pythium and Phytophthora:

Both Pythium and Phytophthora share some common characteristics, such as belonging to the order Peronosporales of the phylum Heterokontophyta, having aseptate hyphae, and producing chlamydospores during asexual reproduction.