Pest of the Month October 2009 – Phytophthora cinnamomi

  • Hosts:  Numerous, including koa, ohia,Norfolk pine, Eucalyptus sp., macadamia nut, hala, avocado, and strawberry guava
  • Range: Hawaii, and most of the rest of the world (Africa, Asia, Australia, Europe, North America, South America, Central America, Caribbean, Micronesia, Fiji, New Zealand, Papua New Guinea)
  • Symptoms:  primarily root rot in Hawaii plants, leading to dieback and death.  Causes trunk cankers in macadamias.
  • Spread through: soil, water, root-to-root contact, movement of contaminated soil or plant debris.
  • Control: alleviation of high soil moisture levels, increasing aeration through improved drainage, and attention to mineral deficiencies.  Systemic fungicides offer some chemical control.

Distribution of Phytophthora cinnamomi – Supprcssive Soil in Nature, Journal of Phytopathology, Volume 127, Issue 1, pp. 75-80, September 1989.

Hwang SC. 1977. Phytophthora cinnamomi: its survival in soil and relation to ohia decline. Honolulu (HI): Cooperative National Park Resources Studies Unit, University of Hawaii at Manoa, Department of Botany. PCSU Technical Report, 12.

Phytophthora cinnamomi,