Beetlemania strikes invasive tamarisk
Beetles with a taste for tamarisk have been enlisted in the fight to rein in the invasive species.
Representatives of the Colorado Department of Agriculture and the Palisade Insectary met Tuesday at Riverbend Park in Palisade to witness the release of 5,000 tamarisk leaf beetles along the Colorado River.
The beetles were provided without cost to the town of Palisade by the insectary as a gift for their continuing support of agriculture.
“We felt like this was a good chance to repay the city for what they’ve done for us over the years,” said Dan Bean, director of the insectary’s biological program.
The beetle release was part of the conference of the Conservation Services Division of the Colorado Department of Agriculture.
Colorado Commissioner of Agriculture John Stulp said he supported biological control of the tamarisk because it was a “win-win-win” situation for farmers, outdoorsman and downstream users of the river.
The insectary is one of only five such facilities in the United States. It began in the 1940s when local farmers turned to biological control to combat the Oriental fruit moth, which was killing the peach crop.
The small, yellow and black tamarisk leaf beetles, similar in size to ladybugs, have been used successfully along the Dolores and Colorado rivers to eradicate the tamarisk, also called salt cedar trees.
Tamarisk is listed on the state’s noxious weeds list. It quickly overtakes the banks of rivers, killing all other native plants and bushes. It also can be removed by applying herbicides or by mechanically removing the roots.
The use of tamarisk beetles is particularly effective when a large area of river bank needs to be treated, biologists said. The beetles often migrate, reproduce, then migrate and populate another area of the river.
Using biological control of the weeds is a slower process, scientists say, but it has proved effective for killing the unwanted weed.
Bean said tamarisk is the only food the beetles eat.
“My view of what will happen here is that the beetles will begin several defoliation cycles in the park, but it will probably be up to three years before you really see something happening,” Bean said.
Bean was careful not to shake the containers or cause agitation to the beetles as he placed them into the tamarisk just off the walking trail in the park. There is plenty of the food source within the park, but he said the beetles could be killed by predators such as ants or birds.