County fights noxious weed on highways
Yellow starthistle has declared war on California’s roadsides. Present in more than 20 million acres of northern California, the noxious weed is spreading toward the southern half of the state at an alarming rate.
Standing in its path is Stanislaus County, which is trying to halt the migration with selective herbicides.
Native to central Europe, the weed was introduced to California around 1850. It flourishes on roadsides, rangelands, hay fields, pastures and waste areas. The infestation is caused by cultivation of the plant, poorly timed mowing and overgrazing by animals. Yellow starthistle grows in dense patches and rapidly depletes soil moisture, preventing the establishment of other plant species.
To control the problem, the Stanislaus County Public Works Department has selected a product by Indianapolis-based Dow AgroSciences. “We needed a product that eliminates harmful weeds but allows the growth of native grasses to prevent erosion,” says Dan Boucher, leadman for the department. “Although we have used selective herbicides for more than 40 years, it wasn’t until recently we became aware of the effectiveness of [the] herbicide on yellow starthistle and other thistles.”
From January to March, Boucher’s crew performed low-volume broadcast herbicide applications for the first time on approximately 2,000 roadside miles. The crew sprayed eight ounces of herbicide diluted in 25 gallons of water per acre.
Already, Boucher sees considerable financial savings on the horizon. In the past, Stanislaus County spent $550,000 a year on manual mowing of starthistle and other unwanted plant species. “Even with the purchase of a new 2,600-gallon spray truck, our herbicide budget will be under $200,000 this year as a result of savings in time and equipment costs,” he says.