Visual, detection tree or purple panel trap survey efforts have been carried out in Wisconsin since 2004 with the goal of finding emerald ash borer as soon as possible where it is present. The state is committed to early detection and thoughtful management of this pest. Surveys have been conducted in high risk areas across the state, including state, federal, municipal and private lands.Purple Panel Trap
Detection traps are the newest tool to assist with EAB detection. The traps are purple, almost three feet tall and one foot wide, and covered with a sticky substance. The adult beetle will stick to the trap if it lands on it.
Traps are placed in the tree canopy or near an ash tree on PVC poles prior to the start of adult EAB emergence and are left up through the end of seasonal beetle flight. Visual Survey Methods
Visual detection surveys for emerald ash borer are conducted from the ground. Surveyors determine if trees are infested by visually scanning them for emerald ash borer-like symptoms and signs.
Due to the high risk of EAB introduction associated with infested firewood,
comprehensive surveillance of areas such as campgrounds, where firewood supplies are generally greater, is viewed as a critical measure. Learn more about emerald ash borer signs and symptoms yourself
and if you see two or more at once, please report your findings. Detection Tree Survey Methods
A detection tree is an ash tree (preferably declining in health) that the surveyor girdles, or wounds, causing the tree to release beetle-attracting chemicals. The tree is typically girdled at waist height and an 18-inch sticky band is placed above the wound. The sticky band, which is used to catch adult beetles, is checked biweekly June through August. Girdled trees are left to stand for one or two growing seasons before they are felled in fall or winter and their bark is removed. Bark removal allows surveyors to detect emerald ash borer larvae and their S-shaped galleries. The larvae are found in the phloem region, sandwiched between the inner bark and outer sapwood. Tree peeling is an essential part of the survey because research has shown that detection trees may be infested with emerald ash borer even if no adult beetles are collected on the sticky band.
To date approximately 2,900 ash trees in 54 counties statewide have been girdled, removed and sampled. Detection tree survey efforts have focused primarily on county, state and federal lands and select municipalities in Wisconsin. EAB has not been detected with this survey method in Wisconsin. However, research has shown that this method is effective at detecting EAB at low population densities. Pending funding availability and additional support from the research community, Wisconsin may continue this work in the future.
Location of EAB traps in Wisconsin in 2016
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Emerald ash borer detection tree, complete with girdle and sticky band.
DATCP surveyors looking for EAB larvae in Delafield in 2008.
Removing suspect beetles from a purple trap in southern Wisconsin.
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