EVE-LYNN SWAN The Standard
UXBRIDGE: The Canadian Food Inspection Agency (CFIA) will visit the north side of Uxbridge’s Elgin Pond in the spring to identify a plant found during the summer of 2018. Goodwood businessman Conrad Richter told The Standard that the agency “has taxonomists qualified to identify Dodder to the species level.”
The alarming plant known as Dodder is of the genus Cuscuta spp. and is a member of the Morning-Glory family (Convolvulaceae). It is an annual, reproducing by seed, but it has a few unusual traits that makes some of its species an unwelcome addition to the landscape. It is a parasite; it has no chlorophyll; it has millions of tiny seeds and those hard seeds can last for 60 years. Once it wraps itself around host plants, it must be physically removed and soil that may contain Dodder seed is scorched to burn the tiny seeds.
Mr. Richter, who runs an herb greenhouse and is very familiar with plants and seeds as part of his commercial activities, was told about a clump of dodder by a former employee who was also alarmed by the discovery of the potentially invasive plant. “I’ve learned from Cathy Shaw that she had made a complaint to the CFIA about [it], and that lead them to me to get more information and I passed on the information. I subsequently reached out to CFIA invasive species unit, and she confirmed that if they find an outbreak, they have to put out an eradication order.” However, “Under CFIA rules they can only go after foreign species. If it is one of 7 native species, they can’t get rid of it. They’ll come out in the spring and identify it.”
Taxpayers can be glad of those plant experts as Uxbridge-area naturalist Derek Connelly wrote in an email that “there are apparently 150- 200 species.” Mr. Connelly was asked to identify the Dodder at Elgin Pond by Bob Ferguson, Arena and Parks Manager for the Township of Uxbridge. “I have some training as a Master Naturalist and am a Director and past president of North Durham Nature Club. At that time I spoke with other naturalists and they were familiar with it as a native plant. At Elgin Pond it was attacking native species. It is nasty but the level of nastiness will depend on the species and its effect on the host plants,” wrote Connelly.
Mr. Ferguson said staff physically removed the mass of plants and returned six weeks later, finding no re-growth. It will be monitored in 2019.
The naturalist was sympathetic to herbalist Richter’s concerns, noting “For a Greenhouse or farming operation I expect concern if this species was invasive or a threat. Proper identification of the plant would be needed and a risk assessment made. This summer would be a good time to re-examine its occurrence at Elgin Pond.”
The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) has a full page dedicated to the plant in its Ontario Weeds Gallery, listing it as a parasitic plant often forming dense, stringy masses. “Being totally without chlorophyll, they must obtain all of their growth requirements from other living green plants around which they wind and become attached. Dodder seed germinates in the soil and sends up a slender… stem without any cotyledons (seed leaves). This slender stem sways or rotates slowly until it touches the stem or leaf of another plant and begins to wind around it… and immediately begins to form haustoria (tiny sucker-like roots). These penetrate the tissues of the host plant and extract all of the Dodder's subsequent growth requirements from it. If the seedling is unable to contact a susceptible plant, it soon withers and dies. Once attached to a susceptible host, the lower end withers and breaks its connection with the ground, while the upper end of the stem grows rapidly, branching and re-branching.”
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