Emerald Ash Borer Signs and Symptoms
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Emerald Ash Borer Signs and Symptoms
by Shawn Bernick, Rainbow Treecare Scientific Advancements
Symptoms
- Symptoms of early infestations may be difficult to diagnose
- As infestation progresses, small vertical splits in the bark can be seen on twigs or trunk
- Typically the top 1/3 of crown dies first and works its way down the tree
- Trees appear to lose about 30%-50% of their canopy after 2 years of infestation.
- Trees may die after 2-4 years or less (small trees)
- As the top of the tree continues to decline epicormic shoots form
- Epicormic shoots can arise at the interface between healthy and dead tissue anywhere in the canopy
- Be on the look-out for multiple declining ash in a given area
- Sapsucker holes and flaking of outer bark near sapsucker holes can be used to detect EAB in early stages
- Distinct “S” shaped frass filled larval galleries that score the outer sapwood and phloem underneath the bark
- Galleries in an affected area can range from 4-20 inches in length
- Galleries from an individual larvae become progressively wider as the larvae grows
- D-shaped exit holes
- (generally present after an infestation has been present for 1 yr. or more)
- Approximately 1/8 inch in diameter
- Dense root sprouting may occur after death of a tree
- Leaf symptoms from adult feeding is usually displayed in small irregular shaped patches along the leaf margins
Signs of EAB - Adults
- Usually bronze or golden green with dark metallic emerald green wing covers
- Adults are slender and can be 1/4 inch to 1/2 inch in length
- Top of the abdomen under the wings is metallic purplish red (seen when wings are spread)
- Adults may be difficult to detect even in areas of high infestation
- Short period of activity (3-6 wks of activity)
- Generally active during the day (sunny and warm days)
- Adults will hang out in bark crevices or on foliage during rain, heavy cloud cover, high winds, or when temps reach above 90 F.
Signs of EAB - Larvae
- Slender, flattened, segmented (10 total abdomen segments) cream colored larvae with a brown head can be found by peeling back loose bark on infested trees
- Larvae range in size from 1 - 1.25" in length
- Pincer-like appendage on the last segment
- Larvae hatch from eggs deposited in bark crevices
If you suspect a possible EAB infestation, call the MDA "Arrest the Pest Hotline" at 651.201.6684 Metro Area, or 1.888.545.6684 Greater Minnesota or send an e-mail to Arrest.The.Pest@state.mn.us - and/or - Contact an ISA certified arborist (click here) |