Disease Cycle
P. capsici is a heterothallic oomycete. The sexual types are designated as A1 and A2. Phytophthora capsici produces both a male and a female type gametangia called an antheridium (male) and an oogonium (female). The antheridium is amphigynous in the species, meaning that the antheridium may remain in this male form of the gametangia or develop into the female gametangia which is an oogonium. Karyogamy between these two types of gametangia one being from the A1 sexualtype and the other of the A2 sexual type results in the formation of an overwintering oospore. The oospores may directly germinate into a germ tube or indirectly germinate and give rise to sporangia which then indirectly germinates and gives rise to zoospores. Zoospores are biflagellate motile spores responsible for the polycyclic qualities of this disease.
Chlamydospores, found in other Phytophthera species, have not been documented on P. capsici in nature or formed on isolates that were collected from a range of hosts and locations.
Read more about this topic: Phytophthora Capsici
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