The Resilience Hub & Portland Maine Permaculture Message Board › Greenhouses/the plant trade
I read the Maine Mycological Assoc. newsletter with interest today. I often comment about the plant trade, greenhouses being the enemy and that the introduction of non natives is often a very bad idea. Here is an excerpt.
February 1, 2014 The Genus Phytophthera, Sudden Oak Death
If only the bad news about Phytophthera were that you feel silly trying to pronounce it. (Try substituting “f” where you see “ph” and be bold and in charge on the second syllable.) But Michaeline, in thanking member Jennifer Davidson for her excellent and detailed presentation, The Genus Phytophthera: Lessons from Sudden Oak Death in California and Beyond, summarized her response in one word: discouraging. A genus first described in 1875, there are 100 described species of Phytophthera (“Plant Destroyer”) and at least 200 more undescribed. Phytophthera ramorum, the species wreaking such destruction among California’s tanoaks, was officially identified
first in Germany when it was discovered on rhododendron branches (hence “ramorum”, “of the branch”). Since 1995 when it was first reported in California, hundreds of thousands of trees, mostly tanoak, along the central coast have died.
It is assumed the tanoak will become extinct. At least two dozen other tree types, such as Black Oak, Coast Live Oak, and Bay Laurel, even redwood, are affected by P.
ramorum but with variable devastating effect. The spores, which thrive in moisture and high temperatures, can reproduce
explosively, and they last for years. They spread via rainwater, streams, and human transportation, i.e., foot treads. Although fog is nourishing, Maine’s climate is probably not sufficiently inviting. However, the species did travel to Maine in 2006 and again in 2012, first via a nursery shipment of lilacs and later of rhododendrons. All but one plant was tracked down and destroyed. Possibly because of ease of transportation through the plant trade, especially of rhododendrons and camellias, the pathogen since 2004 is throughout much of the eastern U.S. as well as in the watershed. It is throughout Europe, as well.