Industry Articles



    Title 35 Article 10 Pesticide Applicators' Act

    Rules and Regulations Pertaining to the Administration and Enforcement of the Pesticide Applicators' Act



    Emerald Ash Borer: What Colorado Communities Need to Know
    April 21, 2014

    With the highly destructive emerald ash borer (EAB) now confirmed in Colorado, many homeowners have questions about their ash trees and the risks presented by the invasive tree insect.

    Late last year EAB was detected in the City of Boulder.

    The insect is already responsible for the death or decline of tens of millions of ash trees in more than 20 states. It poses a serious threat to many of Colorado’s urban forests, where ash species comprise an estimated 15-20 percent of all trees.

    To help homeowners and communities make decisions about dealing with the pest, the Colorado State Forest Service recently released a new Quick Guide about EAB in Colorado.

    Current Recommendations for Colorado:

    • Determine now if you have any ash trees. The first step to dealing with EAB is identifying susceptible host trees on the landscape, which include virtually any species and varieties of ash (genus Fraxinus). Ash trees have diamond-shaped bark ridges, compound leaves with 5 to 11 leaflets, and their leaflets, buds and branches grow directly opposite from one another.
    • Recognize signs of EAB infestation. Homeowners with ash trees should be on the lookout for signs of EAB infestation, which include: thinning of upper branches and twigs, loss of leaves, D-shaped 1/8-inch holes on the bark, vertical bark splitting or increased woodpecker activity. Any suspect trees should be reported to the Colorado Department of Agriculture at (888) 248-5535 or email [email protected].
    • Be aware of EAB imposters. Other insects like lilac/ash borer, ash bark beetle and flat-headed appletree borer may look like EAB or cause similar tree symptoms. For more information, see the new EAB Quick Guide on the CSFS website.
    • Know when treatments are (and aren’t) a good option. Homeowners have the option to apply chemical treatments this spring to help protect high-value trees, but treatments are not recommended more than 5 miles from a positive detection. Currently, the only confirmed in-state detection has been in the City of Boulder.
    • Realize that treatments are necessary to save impacted trees. All ash trees, regardless of species, size or age, can be infested by EAB. Infested trees will not survive without treatments, but treatments can be effective even in infested trees, if infestation is detected early enough.
    • Avoid planting ash trees in Colorado. Ash trees have been widely planted here, but due to the risk of EAB, future plantings are not recommended. However, this spring is a good time to consider planting diverse tree species where ash trees growing now may be lost in the future.
    • Prevent further spread of EAB. Don’t ever transport ash firewood, or any other untreated ash wood products, to other locations. Boulder County and small adjacent areas are now under a federal EAB quarantine, allowing for stiff fines for those who move untreated wood from the area.

    For more information about EAB infestation, treatment options and ash tree identification, view the EAB Quick Guide online or pick up a free copy at the nearest CSFS district or field office.

    For current information about EAB in Colorado, including the current quarantine, go to



    Emerald Ash Borer Control Options

    Can I Save My Ash Tree? Should I?David Merriman

    Destructive Tree Pest Detected in ColoradoColorado Department of Agriculture, September 27, 2013

    LAKEWOOD, Colo. –An invasive insect responsible for the death or decline of tens of millions of ash trees in 21 states has been detected in Colorado for the first time.

    A suspect tree was spotted in Boulder County on September 23rd by City of Boulder Forestry staff. Insect specimens from the ash tree were collected and sent to the United States Department of Agriculture (USDA) Systematic Entomology Laboratory where the identity of the insects was confirmed.

    “The confirmation of these specimens as emerald ash borer (EAB) marks the western-most occurrence of this invasive pest in North America,” said Patrick McPherren, USDA State Plant Health Director in Colorado. “To date Colorado is the fourth State to detect EAB in 2013.” Read More>>

    Emerald Ash Borer UpdateGreenCO

    Mulch For Your TreesJohn Wesolowski, May 2013



    Mechanisms of plant survival and mortality during drought (featured in the Fall 2012 Rocky Mountain Arborist issue)

    Upfront: As diesel prices continue to rise, a groundswell of interest in natural gas vehicles emerges (featured in the Fall 2012 Rocky Mountain Arborist issue)

    Deep-planting techniques to establish riparian vegetation in arid and semiarid regions (featured in the Fall 2012 Rocky Mountain Arborist issue)

    Winter Watering for Drought Stressed TreesDavid Merriman, September 2012

    GreenCO Tree Planting Recommendations June 2012

    Exploiting Allee effects for managing biological invasions Patrick C. Tobin
    As featured in the ISA-RMC Rocky Mountain Arborist Summer 2012 Newsletter

    Wildfires Can Happen Anywhere
    Tree & Landscaping Precautions For Reducing Wildfire Dangers

    Keith Worley, June 2012

    Mountain Pine Beetle – Urban Consideration Joe Cordova, May 2012



    Arbor Day in Colorado Scott Grimes, April 2011

    Hazard Trees for Homeowners Scott Grimes, May 2011

    2011 Tree Climbing Championship Results Chad Delzell, October 2011



    Spring is Just Around the Corner Pete Evers, April 2010

    Pest or Pesticide? Chad Delzell, May 2010

    Are You Ready for Fire Season? Keith Worley, June 2010

    The Fall of the Black Walnut Tree Rob Davis, October 2010

    Winter Watering & Protection James Klett, November 2010

    Winter Care for Trees David Merriman, December 2010



    Prepare Trees for Potential Damaging Weather 2009

    Six Winter Chores for Healthier Spring Trees 2009

    ‘Traveler’ Contractors 2009



    Why Would Anyone Climb a Tree Just to Ring a Bell? 2008

    Articles from Industry Publications

    International Year of Forests backcountry, June 2011

    Emerald Ash Borer Trap Info for Colorado Foresters

    Notice from the Colorado Department of Agriculture regarding Emerald Ash Borer

    Tree man goes to internationals Greeley Tribune, July 21, 2008

    Anti-Beetle Tree Cutting Washington Post