The threat is fungal in origin and it affects North America’s most popular ‘Christmas tree’.
Fraser firs
Most Christmas trees are Fraser firs. These trees are sold around the world in high numbers during December. This type of fir tree is popular due to its ability to hold its needles; as well as other attributes like color and the pine-like smell.
The Fraser fir (Abies fraseri) is a species of fir native to the Appalachian Mountains of the Southeastern U.S.
In terms of the association with Christmas traditions, the Fraser fir has been used far more times as the White House Christmas tree (the official Christmas tree of the President) compared with any other tree.
Other types of Christmas trees:
Fungal disease
All trees are vulnerable to disease and the more botanists learn about plant diseases than the stronger the types of preventative measures that can be put in place (provided that plants and trees are appropriately looked after).
However, the discovery of new plant diseases always proves challenging. A new challenge, to the Fraser fir, arises in the form of a rot-causing fungus – the Phytophthora water molds. The genus Phytophthora has around 170 described species and many of these are pathogenic to plants, causing devastating plant diseases worldwide and leading to severe economic losses each year.
These fungi can prove to be especially devastating to the trees. The discovery of a new species of Phytophthora mold particularly impacts on Fraser firs. The new species is: Phytophthora abietivora.
New disease discovery
Scientists stumbled across the new tree threat as they were conducting work designed to review different ways to grow healthier Fraser firs. This led to a fungus that was affecting tree health. This turned out to be the new Phytophthora species.
Discussing the discovery in a research note, lead scientist Rich Cowles, from the Connecticut Agricultural Experiment Station, says: “Once the organism was isolated, the presence of unusually thick spore walls alerted us that this may not be a commonly encountered species and so comparison of several genes’ sequences with known Phytophthora species was used to discover how our unknown was related to other, previously described species.”
To isolate the fungus and to culture it in preparation for identification, the researchers grew the fungus on apples. This is a mycological test method that dates back to 1931. Here apples are slit and sliverss of diseased tree tissue are introduced and the inoculated apples are incubated over the course of one week.
The researchers hope that further characterization of the fungus will help to combat it. The fungus has the potential to infect tens of thousands of trees; a situation that could well become exacerbated as trees are transported.
Another point of interest is the fact that these scientists so readily discovered a new species further suggests that there could be many more species waiting to be discovered.
Other Christmas tree pathogens
There are other diseases affecting Christmas trees, as the following video explains:
Research paper
The new research has been reported to the Journal of the American Phytopathological Society, Plant Disease. The research paper is titled “Phytophthora abietivora, A New Species Isolated from Diseased Christmas Trees in Connecticut, U.S.A..”
Essential Science
This article is part of Digital Journal’s regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue.
Last week we looked at research going into helping satellites to self-repair and the use of robot satellites to assist with this process. This is seen as something of great economic importance, given the costs incurred when satellites are damaged.
The week before we looked at how science is helping to make beer last for longer (by genetically modifying yeast), a process that might also improve the taste of the alcoholic beverage.
