Spring parsley (Cymopterus watsonii) is a phototoxic rangeland plant that is a member of the Parsely family. It is one of the first plants to begin growing in early spring. It flowers from late April to June and disappears by early summer. Plants are poisonous from early spring until they mature and dry in early summer.
The leaves and seeds of the spring parsley plant contains furocoumarinas, which cause acute photosensitization in poultry. The stems and roots don't contain the photoactive compounds. Affected birds may later develop leg and feet, beak, and comb and wattle deformities as well as reduced eyesight.
In a research study conducted on ducklings in 1978, the birds were fed spring parsley seeds at various doses and exposed to sunlight. Within 8 days, the ducklings developed mild photosensitization with beak deformities.
- Redness and swelling of unfeathered areas of skin (followed by blistering and scabs)
- loss of feathers in the periorbital area
- dried serous fluid on comb and edge of beak
- multiple lesions on feet and legs
- leg and feet deformities
- beak deformities
- reduced eyesight
Spring parsley can be controlled by spraying plants in the bud to early bloom stages of growth with an amine salt of 2,4-D applied at the rate of 1.0 kg per acre of acid equivalent. Follow all precautions for handling herbicides.
- Downie S, Hartman R, Sun F, Katz-Downie D Polyphyly of the spring-parsleys (Cymopterus): molecular and morphological evidence suggests complex relationships among the perennial endemic genera of western North American Apiaceae NRC Canada (2002)
- Morton, J. F. Economic botany in epidemiology. Econ Bot, 32 111-116 (1978)
- Shlosberg, A.; Egyed, M. N. Photosensitization in ducklings induced by seeds of Cymopterus watsonii and C. longipes. Avian Dis, 22(4), 576-582 (1978)
- Egyed, M. N.; Williams, M. C. Photosensitizing effects of Cymopterus watsonii and Cymopterus longipes in chickens and turkey poults. Avian Dis, 21(4), 566-575 (1977)
- Williams, M. C.; Binns, W. Experimental photosensitization by spring parsley (Cymopterus watsonii) in chicks. Am J Vet Res, 29(1), 111-115 (1968)