Does abiotic stress on a plant influence phosphite protection to Phytophthora cinnamomi?

Abstract

Large areas of indigenous forests, Banksia woodlands and heathlands in Australia are devastated by Phytophthora dieback disease caused by Phytophthora cinnamomi (Weste 1994). In southwestern Australia, some 50 percent of the 5710 plants endemic to the region are susceptible (Shearer and others 2004a). Phosphite has been shown to be effective in controlling this pathogen’s impact on a wide range of plant species across different families (Hardy and others 2001). Recently, disease extension was reduced after phosphite treatment even after fire (Shearer and others 2004b). However, very little is known about the influence of a plant’s physiological status at the time of phosphite application on the subsequent efficacy of phosphite treatment to control Phytophthora dieback disease. The key seasonal stresses in an Australian ecosystem of fire and flooding are explored