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Noxious Weeds > Dyer's Woad | Controlling Dyer's Woad | BioControl of Dyer's Woad

Biological Control Methods for Dyer's Woad

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Dyers Woad (Isatis tinctoria) is our enigma here in Northern Utah. A perfectly healthy plant can thrive amongst several others that are wilted and dying. Pictured to the left is a clump containing two or more plants in a field in Weber County. Notice that one plant is very stunted with a curled up look and is surrounded by healthy Dyer's Woad. It is those diminutive stems that are affected with a host specific fungus or rust. It is this fungus that is the hope of the future as far as containing the spread of Dyer's Woad.

There are no known weed feeding insects specific to Dyer's Woad that we know of at this writing. However, this close relative of the Eurasian rust fungus Puccinia thlaspeos is doing yeoman's work in the fight against Woad.

The rust can enter the plant through inoculation on the leaf surface and systemically damages the plant to the roots. It can prevent or reduce seed production and may also affect the survival of seedlings, rosettes, and overwintering plants. Researchers are not sure of the identity of this species and are uncertain as to how it moves through the plant. The rust is able to complete its life cycle on I. tinctoria alone and does not seem to require a secondary host like many rusts do. Photo below is of a rust infected Woad plant in Huntsville, rural Weber County.

Utah State University has received grant monies to study the biology of the rust and we are hopeful that we will be able to spray or dust infestations of Dyer's Woad at our convenience rather than waiting for nature to mysteriously move the rust around. In the meantime, we in Weber County welcome anyone who wishes to dig up and pot a few infected Dyer's Woad plants from our collection and transplant them among their non-rust bearing Woad patches. This method works quite well and has been used often the last several years.
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Noxious Weeds > Dyer's Woad | Controlling Dyer's Woad | BioControl of Dyer's Woad