White-Tipped Canada Thistle is not an "Albino Strain."
Canada thistle (Cirsium arvense) plants that are infected with the bacterium Pseudomonas syringae pv. tagetis (PST) develop "bleached tips." The bacterium produces a chemical called tagetitoxin that is a RNA polymerase III inhibitor that blocks the production of chloroplasts. Symptoms could be mistaken for exposure to a member of the photosynthesis inhibiting class of herbicide such as the triazines (e.g. atrazine) and nitriles (e.g. bromoxynil). Of course, the herbicides would tend to affect the entire plant whereas PST only affects the upper portions of...