Separating the good from the bad in Rio Blanco bugs

Tamarisk Beetle. Photo by Sarah Zukoff on Flickr: https://www.flickr.com/photos/entogirl/13979146776/in/photostream/
Listen to this post

PRESS RELEASE | Special to the Herald Times

RBC | Rio Blanco residents had their “antennae up” as bug expert Nina Louden from the Colorado Department of Agriculture — Insectary shared her observations and knowledge about how to put bugs to work and save money for Rio Blanco County and area landowners as they fight expensive invasive plant infestations.

Last month at the Heritage Culture Center, the White River Alliance hosted Louden, a specialist from the insectary in Palisade, Colorado, whose primary expertise is with tamarisk-eating beetles. Louden presented details on beneficial insects that are available at the insectary to help landowners battle tamarisk, leafy spurge, Canada thistle, Russian knapweed, toadflax and others.  

They have seen good success with the tamarisk beetle in Douglas Creek but it has not spread up the White River, possibly because of past mosquito aerial spray. After bugs kill back branches over at least two or more consecutive years, tamarisk can be cut, but herbicide must be applied to the stump right away otherwise it will re-grow.

Louden explained bio-controls do not eradicate invasives like tamarisk but are critical in slowing their spread and with other tools can vastly minimize the infestation. Certain areas have better success. The outcome seems related in some cases to aerial mosquito spray or fogging which diminishes impact by killing beneficial insects such as tamarisk beetles. Delta, Colorado, currently treats for mosquitos using mosquito specific larvicide or Bti and less frequent, more targeted mosquito fogging and is now having success with beetles on their tamarisk stands. Beetles are the most cost-effective tool compared to labor, chemicals and machines. 

Why is tamarisk bad? Tamarisk makes soil salty thus eliminating native plants. It can make a river unapproachable for humans and wildlife by creating a monoculture, killing native inhabitants, and thus end up using more water than natives due to prolific growth. 

It is the tamarisk beetle larvae that feed on the plant. Larvae eat leaves and flowers, slowing tamarisk spread. One can expect up to 55% die-back, and about 30% killing of the whole bush. 

When asked about bugs for Russian olive and houndstongue, Louden she shared that a mite is being considered for Russian olive which will reduce seeding and they are hopeful for the arrival of a weevil for houndstongue. The weevil has been a big success in Canada, but is not available here yet. 

She explained that the typical aerial spray or fogging with Permethrin kills all insects on contact: as well as bees, butterflies and the beneficial bugs distributed to ranchers and landowners by the insectary. Many areas have turned to a natural compound called  Bti which is used to kill the larvae and is much more effective. Unlike Permethrin, Bti does not kill other insects and does not harm Tamarisk beetles. 

She also shared the impact of aerial mosquito spray (permethrin,etc.) on these beetles (kills them dead), adding that areas that cease to use aerial permethrin and instead use more targeted mosquito control or Bti will have far greater luck with reducing Tamarisk using tamarisk beetles than those that don’t. 

She also shared that many areas around the state are moving to larvae control (rather than adult control) for mosquitos as it is cheaper, more effective and healthier for both people and beneficial insects. 

Delta County, for example, has found the most cost-effective way to treat mosquitos is to focus their efforts on early larval treatment before the adults get bad. They identify and work to remove wet areas and deposit Bti, which is a natural substance that kills the larvae before they develop into adults. Larval controls (Bti) are extremely effective and non-toxic to horses and livestock. Aerial fogging has not been used in Delta County since the late 1980s to early ‘90s.

If all the hot spots aren’t adequately treated using bacteria a very short lived mineral oil (BVA 2 oil) can be applied to water surfaces to kill mosquito pupae. Interestingly, diesel used to be used. If these methods do not work — including first and foremost removing standing water when possible, proper drainage of irrigated fields and such, then fogging is necessary to control adult populations. Fogging with trucks or backpack sprayers are used when necessary on residential properties or areas where adult mosquitoes are found, then Pursuit insecticide is used. Without proper larvicide treatment adult mosquitos will be prevalent and more fogging is necessary. 

Actively applying host specific bacteria with backpack sprayers or other methods to standing water is the way to prevent adults from ever forming. The White River Alliance pest management committee will continue to research surrounding counties efforts in this area to assist in spreading best and most cost effective practices.

In other news, the White River Alliance voted to provide an annual scholarship for a Rio Blanco youth who shows leadership in the area of conservancy in the name of Anthony Weiss, who just passed away, and was known for his work, love and dedication to the outdoors. 

Liz Chander, one of the new coordinators for the White River Integrated Management Plan gave a brief update on activities within the Planning Advisory Committee which will include a study on diversions and a healthy riparian. And finally, a Clean Up the White River Day was set for May 22 starting at 8:30 a.m. up at Lake Avery and moving down to Circle Park and finally the 10th Street Bridge. Lunch will be provided and the public is invited to help.

Area pilot David Cole reported that he had been engaged by the Water Desk at Colorado University to fly over the White River from Trappers Lake to Utah to video the river from headwaters to Utah with a GoPro camera to create a video library to assist journalists in reporting on river issues. The videos will be posted at the Rio Blanco Times Herald website. 

All are invited to help with Clean Up the White River Day and to join or learn more about the White River Alliance at whiteriveralliance.net.