Emerald Ash Borer (EAB) is considered the most destructive forest pest ever seen in North America. According to the Colorado Department of Agriculture, this green metallic beetle was found near 30th and Iris in North Boulder and on the University of Colorado campus during the fall of 2013. Durning the month of June 2016 the emerald ash borer was foiund inside the city limits of Longmont. EAB is responsible for killing more than 50 million ash trees in over 20 states. To put this in perspective, the Mountain Pine Beetle is responsible for devastating much of our Colorado mountain forests and if left untreated the Emerald Ash Borer will do the equivalent to our urban forests. The Colorado Department of Ag estimates that one in five trees in Colorado is an ash tree. The good news is there are preventative measures to protect ash trees.
To mitigate the potential for damage/loss to ash trees, Organo-Lawn strongly advises all of the following actions and services for all ash tree.
Emerald Ash Borer
Trunk Injection for Emerald Ash Borer – For ash tree care residents that live inside the city of Boulder, Niwot, Longmont, and Lafayette Colorado.
Preventative measures should be taken because initial detection of EAB can be difficult and it may take up to five years for the canopy of an infested ash to thin and decline. Since borers infest the upper branches of the tree, the “D”-shaped holes cannot be seen from the ground until the tree is severely infested.
Where did the emerald ash borer come from?
Emerald ash borer (Agrilus planipennis), was introduced accidentally into Michigan possibly from wood packing material imported from eastern Asia sometime in the 1990’s. It became well established in Michigan until ash trees started dying in 2002, when it was first detected. It is responsible for the deaths of tens of millions of ash trees in the Midwest and eastern U.S.
How long has the emerald ash borer been in Colorado?
The emerald ash borer was first detected near 30th and Iris in North Boulder, CO. on September 23rd, 2013. It was confirmed on September 26th, 2013. At this time, it has also been found in South Boulder and on the University of Colorado campus. It has been found in every part of town in Boulder and was discovered in Longmont on June 6th, 2016. According to the Department of Agriculture, it may have been in Colorado since 2010.
Does Emerald Ash Borer attack trees other than Ash?
No, it will only attack ash trees.
Click to Enlarge
Woodpecker activity and damage increases where they are trying to get to the larvae in the tree.
Canopy die-back will begin at the top of the tree progressing downward until the tree is bare.
Later stages of infestations, ash trees may form sprouts from the trunk and/or roots.
Bark splitting may occur exposing “S”-shaped galleries caused by the larvae of the EAB.
Although difficult to see, the adult beetles leave a “D”-shaped exit hole in the bark, roughly 1/8 inch in diameter, when they leave the tree as an adult.
Emerald ash borers are a bright, metallic-green color. They are approximately ½” long and have a flattened back. They can be mistaken
for other green insects, so a positive identification by a professional is necessary.
Emerald Ash Beetles emerging from an ash tree.
EAB emerging from an ash tree in Fort Collins.
Click image above to view diagram
Adults emerald ash borer's emerge between mid-May through late July, and they will feed on ash leaves (this is where the preventative Merit or Safari insecticides will provide protection). They mate, and then the females lay eggs (average of 60-90 per female) in bark cracks. Larvae hatch from the eggs within one week and then bore through the bark and into the trunk of the tree. The larvae then feed under ash tree bark from mid-summer through the next spring, producing the “S”-shaped tunnels (This is where Tree-Age will provide control). They pupate in the spring and the next generation of adults may emerge.
How far can EAB travel?The EAB adult flies ½ - 1 mile a year. However, borers can also be spread via the transportation of firewood from infested trees.
Very Important: NEVER move ash firewood from ash trees out of the area.
Does it only attack dying or stressed trees?No, whereas most boring insects tend to prey upon stressed or weakened trees, emerald ash borer may attack both healthy and stressed trees; but a healthy tree will have a better chance of surviving an attack than a weak tree.
How big of problem is EAB?Huge! It is a major problem that should not be ignored. The Emerald Ash Borer is now considered the most destructive forest pest ever seen in North America. It has killed tens of millions of ash trees in southern Michigan alone.
How do I know if an ash tree is infested with Emerald Ash Borer? Initial detection is not easy. It may take 4-5 years for the canopy of an infested ash to thin and decline. When a tree shows thinning a decline it is usually too late to save. Since borers infest the upper branches of the tree, and they only make the D shaped holes upon exiting the tree the D shaped holes may be seen until the tree is severely infested. Long story short is it might be impossible to tell if a tree is infested, until it is too late. This is why preventative measures are so important when dealing with the EAB.
Is Organo-Lawn doing applications of Treeazin? At this time we are recommending applications of Tree-age instead of Treeazin. We are suggesting this because Tree-age has a significantly higher control rate and provides control for a longer period of time. We will be doing more research into Treeazin for possible future use, but at this time we consider Tree-age applications to be a better choice for control of the Emerald Ash Borer.
Which Colorado Cities to treat ash trees using Tree-age trunk injections include:
Which Colorado Cities to treat ash trees using soil injections include:
Note: If you live in Arvada, Golden Westminister, Broomfield, Ft. Collins, Loveland, Laporte, Windsor, Frederick, or Firestone you do not need to treat for EAB, but these recommendations might change quickly in the near future. We are suggesting preventative treatments for high value trees.
Why is proper deep root tree fertilization important for ash trees?
The healthier a tree is the better it can fight off and/or survive attacks.
Why is Winter Tree Trimming important for ash trees?
Removing dead branches and creating a strong structure is always beneficial for a tree and will only make the tree healthier.
Are aerial sprays effective against EAB?
No, EAB feed in the tree differently and will not be controlled via sprays. Merit Soil injections will work only if in the tree has not been attacked and trunk injections will work both if it has been attacked and before an attack.
Are there any ash trees you do not recommend treating?
The only ash trees that are not worth treating are ash trees that are weak, severely stressed, and are already struggling because of improper planting, lilac ash borer, heat stress or other problems that will make the tree unlikely to be able to absorb the trunk or soil injections. These trees are not worth treating because they are probably not going to live but a few years anyways.
If you have any questions about Emerald Ash Borers in Colorado please contact Organo-Lawn, your local tree care expert. Boulder (303) 499-2000 Fort Colins (970) 225-9425