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Rachel Winston at the Forest Service Slate Creek yellowstar thistle bio control monitoring transect.

Bio-Control

In 2009, Idaho County Weed Control, in conjunction with the RAC, US Forest Service, USDI BLM, and MIA Consulting, initiated a biocontrol monitoring program to determine the effectiveness of numerous releases that have occurred throughout north central Idaho since 1979. Four weed systems were monitored utilizing the Standardized Impact Monitoring Protocol. These efforts were repeated and expanded in 2010 and 2011. A total of 57 permanent monitoring sites spanning seven weed species were visited throughout the 2011 growing season. For Dalmatian toadflax, insects appear to be contributing alone or in combination with favorable spring weather to the weed’s control at 11 sites, have no impact at two others, and more time is needed to draw conclusions at one final site. In the spotted knapweed system, insects have likely been a major contributor in the weed’s control at one site, they may be slightly effective at another site, and appear to be ineffective at all others, though more time is needed for sites where agents were released as recently as 2009.

For leafy spurge, insects have been the only consistent form of weed control at two sites, and they have effectively reduced the weed to small, relic populations. In the yellow starthistle biocontrol system, several years of biological control have not impacted the weed significantly; yellow starthistle is still the dominant species at all sites monitored. Three additional weed monitoring systems (field bindweed, houndstongue, and whitetop) are pre-release systems only. Sites were established on these weeds in 2010 and monitored again in 2011 for the purpose of gaining baseline data prior to the anticipated future approval and release of new biocontrol agents. Finally in 2011, a more intensive study was initiated on the spotted knapweed biocontrol system in order to identify trends in establishment, abundance, and efficacy of insects in the Clearwater Basin of Idaho County where biocontrol has been one of the widest forms of control utilized against spotted knapweed for the past three decades. Results from this study are still being analyzed.

Interface Areas

The RAC interface area project includes road weed treatment of USFS property connected to Idaho County, and interface areas of private property adjoining USFS property.  Nearly 750 miles of key road networks within the Salmon River, South Fork Clearwater, and Selway River Drainages have been monitored and treated to insure noxious weed growth is deterred.  These applications have been spot-spray, in nature, unless large infestations were reported. Two local, start-up businesses have benefited from this work.  They collect inventory data, treat the infested sites, record their treatment, and evaluate the work at a later time. This RAC project continues to be extremely important in keeping weeds on the public land from infesting private land, and vice versa. 

New Invaders

The RAC New Invader project is intended to provide funding to attack plants that are new to the county or parts of the county.  This funding provides labor to visit the sites of these new invading species a minimum of three times during the current growing season, and not allow that plant to reproduce.  In a county as large as Idaho County this is a difficult assignment.  However, crews have visited over 2500 sites to insure the plants were not reproducing.  During these visits, a new weed was recorded for Idaho County, viper’s bugloss.  This plant infested about 40 acres at its time of discovery.  All acres were treated with RAC funding, and repeat visits and treatments were made.  It is critical to land health, to continue to eradicate new invaders.