Fall Plant Control of cressleaf groundsel; Prevent the sea of yellow in the spring

– Dr. Diane Gerken, DVM, ABVT Veterinary Toxicologist

ODA’s Animal Disease Diagnostic Lab has been involved in two separate cases with animals affected by the toxicity of this plant in the past year.

This plant is Senecio glabellus or now called Packera glabella which occurs in some uncultivated Ohio fields. This is a picture indicating possible plant density in the springtime. If you made hay/haylage with this plant in it, the recommendation is to NOT feed it to livestock or horses. Also, do not use as pasture for any grazing animal.

ODA-ADDL personnel have been involved in two separate cases (one with classic pathology and the second with a positive chemical analyses for the specific pyrrolizidine alkaloids in this plant) with animals affected in the past year. This plant contains at least one toxic pyrrolizidine alkaloid (PA), senecionine but reported to contain more. Pyrrolizidine alkaloids cause liver disease in humans and animals after either acute or chronic exposure to contaminated feed/food.

The liver is the primary target tissue of toxicity resulting in the signs of anorexia, depression, icterus, visceral edema, and ascites in acute exposures. The chronic exposure signs are photosensitivity, icterus, increased susceptibility to other liver diseases or there may be no overt signs except failure to thrive. These alkaloids are liver-bioactivated to toxic metabolites (pyrroles), which remain in the liver for long periods of time (perhaps months to years) causing cumulative cellular cytotoxicity. Also In many animals (ruminants and horses), once ingested, absorption from the gastrointestinal tract can continue to occur over weeks even if not ingested again. Younger animals are more susceptible that older ones. Animals with marginal nutrition are more susceptible than ones with good nutrition. Poultry are also susceptible. Females excrete PAs in their milk so nursing animals will be exposed and for humans, there is a public health issue due to the milk contamination.

Why is this important now? To prevent further exposure to these plants in pastures and hay fields, the preferred time to control this plant is in the fall. websites for herbicide selection and timing of application from field trials are http://bulletin.ipm.illinois.edu/?p=3750 and http://bulletin.ipm.illinois.edu/?p=3589. Other sources of information: https://agnr.osu.edu/sites/agnr/files/imce/pdfs/Beef/Cressleaf.pdf and https://bygl.osu.edu/node/706.

EDITOR’s NOTE: Also see these articles from previous issues of the Ohio BEEF Cattle letter for more information on fall control of cressleaf groundsel, poison hemlock and other biennial and perennial weeds in the fall.

Scout for, Control Cressleaf Groundsel This Fall

NOW is a Great Time to Control Next Year’s Poison Hemlock

Perennial Weed Control in Grass Hay and Pasture

Get After the Weeds Yet This Fall

Pasture and Forage Weed Control; Mow or Spray?