Phytophthora heveae
| Phytophthora palmivora | |
|---|---|
| Scientific classification | |
| Domain: | Eukaryota |
| (unranked): | SAR |
| Superphylum: | Heterokonta |
| Class: | Oomycetes |
| Order: | Peronosporales |
| Family: | Pythiaceae |
| Genus: | Phytophthora |
| Species: | P. palmivora |
| Binomial name | |
|
Phytophthora palmivora Butler |
|
| Synonyms | |
|
Phytophthora arecae (L.C. Coleman) Pethybr. |
|
Phytophthora arecae (L.C. Coleman) Pethybr.
Phytophthora cactorum var. arecae (L.C. Coleman) Sacc. & Trotter
Phytophthora faberi Maublanc
Phytophthora omnivora var. arecae L.C. Coleman
Phytophthora palmivora var. theobromae (L.C. Coleman) Orellana
Phytophthora theobromae L.C. Coleman
Pythium palmivorum Butler
Phytophthora palmivora causes bud-rot of palms, fruit-rot or kole-roga of coconut and arecanut. These are among the most serious diseases caused by fungi and moulds in South India. It occurs almost every year in Malnad, Mysore, North & South Kanara, Malabar and other areas. Similar diseases of palms are also known to occur in Sri Lanka, Mauritius and Sumatra. The causative organism was first identified as Phytophthora palmivora by Butler in 1917.
Phytophthora palmivora produces abundant sporangia on V-8 agar under continuous fluorescent light. However, light is not required for sporangia production on infected papaya fruit. Sporangia are usually produced in clusters sympodially. Sporangia are papillate and ovoid with the widest part close to the base. They are easily washed off and each detached sporangium contains a short pedicel. The average size of the sporangia is 50 X 33 µm with a length of about 1.6 times longer than it is wide. Sporangia germinate directly in a nutrient medium by producing germ tubes that develop into mycelial masses. In water, however, zoospores are released from germinating sporangia. Zoospores aggregate and form distinct patterns at 16 °C in water.
Chlamydospores produced in infected papaya fruit and pure papaya juice are thick-walled. However, chlamydospores produced in papaya juice at lower concentrations or in other kinds of fruit juice are mostly thin-walled. In the presence of nutrients, chlamydospores germinate by producing germ tubes that continue to grow and form mycelial masses. In water, chlamydospores germinate by producing short germ tubes, each with a sporangium at the tip.
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Wikipedia