Emerging Pest Alert

First detection of Phytophthora tropicalis in the continental United States

Scientific Name: Phytophthora tropicalis

Describer: nan

Common Name: nan

Title: First detection of Phytophthora tropicalis in the continental United States


Significance: In North America, Phytophthora tropicalis has previously only been detected in Hawaii of the United States. Recently it was confirmed on leaves of Pieris japonica and Rhododendron catawbiense taken from a garden center in Virginia Beach, Virginia (VA) in 2004. Researchers at VA Polytechnic Institute and State University also confirmed Phytophthora isolates collected in 2000 and 2001 from irrigation water at a production nursery in Suffolk, VA as well as isolates from soil samples taken from two mixed-hardwood forests in Fairfax County, VA in 2002 to be Phytophthora tropicalis.

Issues of Concern: Although damage to the nursery plants in VA were minimal, these findings demonstrate an expanding host range for Phytophthora tropicalis as well as the feasibility of irrigation water used in nurseries to be infested with Phytophthora species.

Hosts: Besides those reported above, Aragaki & Uchida (2001) reported P. tropicalis on Annona cherimolaAnthurium andraeanumCarica papayaDianthus caryophyllusHedera helixLeucospermum sp., Macadamia integrifoliaRadermachera sp., Sechium eduleSolanum melongena (all from Hawaii) and Theobroma cacao (from Brazil). It has also been reported on Artocarpus altilius from Brazil by Cequiera et al. (2005). There was also a report of it from Germany and the Netherlands on Cyclamen persicum (Gerlach & Schubert, 2001).

Comments: If you have any further information about the distribution or hosts of this species, please let us know. 


Hong, C.X., Richardson, P.A., and P. Kong. 2006. Phytophthora tropicalis Isolated from Diseased Leaves of Pieris japonica and Rhododendron catawbiense and Found in Irrigation Water and Soil in Virginia. Plant Disease. 90(4): 525.

Other references used:
Aragaki, M. and J.Y. Uchida. 2001. Morphological distinctions between Phytophthora capsici and P. tropicalis sp. nov. Mycologia. 93: 137-145.

Cerquiera, A.O, Luz, E.D.M.N, and J.T. De Souza. 2005. First record of Phytophthora tropicalis causing leaf blight and fruit rot on breadfruit in Brazil. New Disease Reports, Vol. 12. The British Society for Plant Pathology. Available online at: http://www.bspp.org.uk/ndr/jan2006/2005-73.asp

Gerlach, W.W.P. and R. Schubert. 2001. A new wilt of cyclamen caused by Phytophthora tropicalis in Germany and the Netherlands. Plant Disease. 85: 334.