Scientists and partners from the United States Department of Agriculture's (USDA) Agricultural Research Service (ARS) have verified the existence of a newly identified mite in France, which may serve as a biological control agent for the invasive tree-of-heaven, or Ailanthus altissima.
According to the research, which was published in Phytoparasitica, this is the first time that the mite species Eriophyid has been reported in the country.
“In Europe, this Eriophyid mite is considered one of the most promising biological control agents of tree-of-heaven,” Javid Kashefi, senior support scientist at the European Biological Control Laboratory (EBCL) near Montpellier, France said in a USDA press release. “This finding provides encouraging evidence that the geographic occurrence of this species is expanding in the continent.”
The tree-of-Heaven, native to northeast and central China, is an invasive plant species that was introduced to the U.S. and Europe in the 1700s, the release said. It is harmful to vegetation and can cause damage to pavement and building foundations.
Eriophyid mites, which are microscopic and live in large groups underneath young leaves, cause plant leaves to curl and look yellowish in color, the USDA said. Once infected, a plant's growth is slowed. Several Eriophyid mites have been confirmed to be host-specific, which is beneficial for scientists researching biological control agents for invasive species such as tree-of-heaven.
Kashefi first discovered the mites after observing trees exhibiting leaf rolling consistent with Eriophyid mite infection in May 2020 while conducting field observations at a park in Colombes, France, the release said. In August and September 2020, four additional mite populations were discovered in various locations around southern France.
“The presence of this species in France is indicative of their dispersal and establishment abilities, two key factors for a successful, future biological control program,” Kashefi said in the release.
