VACAVILLE — The orders were to inject some invasive plants and to spray others along Pleasants Creek in rural Vacaville.
Those instructions were mixed up somewhere along the way and resulted in around 12 dead oak trees and 20 to 30 more that were damaged.
An investigation by the Solano County Department Agriculture is currently underway, said Simone Hardy, assistant agricultural commissioner.
Hardy said Wednesday that “there seem to be some issues” with the application of the chemicals.
The issue in question took place during an eradication effort to rid the creek beds of Arundo and Tree of Heaven, which are non-native species that cause erosion and water flow problems in the creek, said Rich Marovich, streamkeeper with the Lower Putah Creek Coordinating Committee.
Marovich said with regret that crews from the contracted Agrichem Industries in Davis mixed up orders to inject one species and spray the others. That led to overspray landing on the oak trees, killing the dozen or so, he said. Marovich said it was the first time in 12 years of using the company that such an incident had occurred.
“The spray crew just mistook their marching orders. They treated the plants in mixed canopies,” Marovich said. “I was certainly dismayed with the amount of overspray. I feel terrible this happened. We don’t want to be hurting native populations.”
Paul Washburn, owner of Agrichem, confirmed the crew mixed up the orders and said he regretted the error.
“They didn’t mean to do that,” Washburn said. “It won’t happen again. I can guarantee you that.”
Arundo is likened to bamboo that grows in thickets, making the spray method the best to kill it. Tree of Heaven, brought over from China, is more susceptible to injecting the herbicide into the plant itself given that it is commonly found among other plants, Marovich said.
The spray is treated with a blue dye to help crews see where it is landing, which in this case was also in the water, Marovich said. Residents near where the damage occurred soon noticed the water had a bright blue color, which caused concerns.
“I would be (concerned), too,” he said. “You see that water an unnatural blue and the first thing you think is it’s a septic tank or some other toxic material.”
The spray is considered “relatively nontoxic to aquatic species,” he said. The California Department of Fish and Game inspected the area. Marovich said they noted seeing species still living in the area and would later issue a report on the findings.
Hardy agreed and said there was likely no risk to the water, but the damage was done to the plant life.
Marovich said the dead oaks would be replaced and even offered to have the landowners personally pick out the new trees from the nursery in Davis the group regularly uses. In areas where larger trees were killed, he said several would be planted in their place.
He said the irony of the whole situation is they are there to protect the native species and plant new trees once the non-native species are killed off.
“We will be leaving it in better condition eventually, but we didn’t want to take a step back doing it,” Marovich said.
Any land owners or others who want more information about the incident or the replacement of trees can call Marovich at 530-902-1794.
Reach Danny Bernardini at 427-6935 or [email protected] Follow him on Twitter at www.twitter.com/dbernardinidr.