Phytophthora pluvialis explained

Phytophthora pluvialis is a semi-papillate plant pathogen that mainly infects tanoak-Douglas-fir forests of western Oregon.^[1] It was reported in Cornwall. UK, in October 2021; the first record for Europe.^[2]

Description

Phytophthora pluvialis is homothallic; it forms oogonia in culture. Its oogonia are terminal, smooth and globose, being approximately 30 μm in diameter, and possess amphigynous antheridia. Its oospores are globose and aplerotic, being about 28 μm in diameter. Sporangia formed in water are ovoid and slightly irregular, semi-papillate, terminal or subterminal, and partially caducous with medium-sized pedicels.

Further reading

• Dick, Margaret Anne, et al. "Pathogenicity of Phytophthora pluvialis to Pinus radiata and its relation with red needle cast disease in New Zealand." New Zealand Journal of Forestry Science 44.6 (2014).
• Hood, Ian A., et al. "Decline in vitality of propagules of Phytophthora pluvialis and Phytophthora kernoviae and their inability to contaminate or colonise bark and sapwood of Pinus radiata log segments." New Zealand Journal of Forestry Science 44.1 (2014): 7.
• Rolando, Carol, et al. "The use of adjuvants to improve uptake of phosphorous acid applied to Pinus radiata needles for control of foliar Phytophthora diseases." New Zealand Journal of Forestry Science 44.1 (2014): 1–7.

Notes and References

1. Reeser. P.. Phytophthora pluvialis, a new species from mixed tanoak-Douglas-fir forests of western Oregon, U.S.A. North American Fungi. 2013. 1–8. 1937-786X. 10.2509/naf2013.008.007. free.
2. News: 'Robust action' taken against tree disease found in Cornwall . BBC News . 22 October 2021 . 13 November 2021.