Summer is when dallisgrass shows itself along roadsides, pastures, hay fields and lawns. It puts up a distinctive seed head that is easy to spot, even at highway speeds. Although dallisgrass is not welcome by golf course turf managers or home lawn enthusiasts, it is welcome in horse and cattle pastures.
Most pastures and hayfields are a predominant mix of cool season grasses such as fescue, orchardgrass, and bluegrass. However, dallisgrass and other warm season grasses such as crabgrass, eastern gamagrass, and johnsongrass are important pasture forages for livestock in heat of June, July, and August when cool season grasses are less productive.
Pictured is a dallisgrass seed head. Once dallisgrass seed heads ripen they can be infected with an ergot fungus. Infected seed heads are black and sticky. The ergot fungus produces a toxin that affects the central nervous system of cattle. This condition is called “dallisgrass staggers”. As the name implies, the animal staggers like a drunken sailor. This generally does not harm the animal. In severe cases lack of coordination causes the animal to hurt itself when stumbling into objects. To avoid the problem farmers can clip the seed heads off the pasture with a mowing machine.
A close cousin to the fungus that causes dallisgrass staggers in cattle has been suspected in having a role in the Salem Witch trials of 1692 and 1693. Cereal rye, used in bread flour, may have been contaminated with an ergot fungus. This could have caused some of the bizarre behaviour claimed to be taking place. Today feed and food grains are tested for fungal contamination that can harm us.
This year’s wet weather may make dallisgrass staggers an issue for local cattlemen. If there are black sticky dallisgrass seed heads in the pasture, it is advisable to clip them off before turning cattle or horses into the pasture.