Colorado and the Emerald Ash Borer
By David Cromley
David Cromley is a sales rep and branch manager for Helena Chemical Company in Denver, CO. David has worked in the Green Industry since 1984 and has served on the board of directors for several industry associations including the RMRTA, CALCP, CSTMA and the Colorado State University IPM Advisory Board.
It’s fitting the call I received that the emerald ash borer (EAB), Agrilus planipennis, was in Colorado happened on a rainy September 2013 afternoon on my way back from Cheyenne, WY. We had just finished the early fall ISA meeting. The discovery of EAB in Missouri months before had us convinced we were probably two years away from finding in Colorado. With that big, natural barrier called Kansas and Nebraska, no way it could travel that fast?
Having seen the signs while water fowling in Saskatchewan and at the family reunion in Wisconsin Dells about not moving firewood, imagine my surprise when foresters in Boulder added Colorado to the list of 24 states being attacked by the highly destructive, green menace. Colorado already had signs on many vehicles from the Mountain Pine Beetle: “Don’t move Firewood, it BUGS me”. Now the true native North American ash trees (green, white, black and blue) were in trouble. Colorado’s urban and community forests are made up of 16%-18% ash; metro Denver alone has approximately 1.45 million ash trees.
The first EAB in CO was detected in Boulder but has now also been found NE of Boulder in Longmont. From what we know of this devastating pest, it won't be confined to these areas for long. Colorado was fortunate to have researchers and foresters from many NE communities to draw information from, including those who have already spent billions of dollars to treat, remove and replace their Ash.
Colorado Helena was fortunate to have spent the previous 7 years preparing for the new pest. Currently, three systemic treatments have proven effective; imidacloprid as a drench, Safari with Helena’s Kinetic as a trunk spray and the Arborjet trunk inject using the RUP, TreeAge, active ingredient emamectin benzoate. The TreeAge allows for two years of control and also controls the Ash Lilac Borer, a common Ash pest in the Rockies. The other two apps give a year of control and no ALB control. Natural controls have been released in Boulder, three different parasitic wasps are being monitored. It should also be noted a General Use TreeAge (G4) has just been labeled in Colorado; Helena still recommends the use of arbor professionals with the need to drill and set plugs in the trunk. Even with the Ash tree being wind pollinated, all arborists are encouraged to be aware of pollinator timing.
Check out these links for more info on the identification and treatment of EAB: