Building Double-decker Traps for Early Detection of Emerald Ash Borer

Summary

Effective traps to attract and capture the emerald ash borer (EAB) are a key element of detecting and managing this invasive pest. Double-decker traps, placed in full sun near ash trees, incorporate visual and olfactory cues and were more likely to capture EAB than other trap designs in field trials.

Abstract

Emerald ash borer (EAB) (Agrilus planipennis Fairmaire), the most destructive forest insect to have invaded North America, has killed hundreds of millions of forest and landscape ash (Fraxinus spp.) trees. Several artificial trap designs to attract and capture EAB beetles have been developed to detect, delineate, and monitor infestations. Double-decker (DD) traps consist of two corrugated plastic prisms, one green and one purple, attached to a 3 m tall polyvinyl chloride (PVC) pipe supported by a t-post. The green prism at the top of the PVC pipe is baited with cis-3-hexenol, a compound produced by ash foliage. Surfaces of both prisms are coated with sticky insect glue to capture adult EAB beetles. Double-decker traps should be placed near ash trees but in open areas, exposed to sun. Double-decker trap construction and placement are presented here, along with a summary of field experiments demonstrating the efficacy of DD traps in capturing EAB beetles. In a recent study in sites with relatively low EAB densities, double-decker traps captured significantly more EAB than green or purple prism traps or green funnel traps, all of which are designed to be suspended from a branch in the canopy of ash trees. A greater percentage of double decker traps were positive, i.e., captured at least one EAB, than the prism traps or funnel traps that were hung in ash tree canopies.

Introduction

The emerald ash borer (EAB) (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae) has killed hundreds of millions of ash (Fraxinus spp.) trees since it was first identified in 2002 in the greater Detroit, Michigan metropolitan area and in nearby Windsor, Ontario, Canada. Inadvertent spread of infested ash trees, logs and firewood, along with natural dispersal of beetles, have resulted in EAB establishment in at least 27 states, and two Canadian provinces to date¹. Recent reports indicate the EAB has also invaded Moscow, Russia, where it is killing landscape ash trees^2,3<....

Protocol

1. Prepare the Green and Purple Panels

1. Acquire green and purple corrugated plastic panels (120 cm × 60 cm) for EAB trapping from a commercial distributor of pest management supplies. Use a box-cutter or utility knife to score two fold lines in each panel by partially cutting through the plastic along the vertical corrugations, 40 cm from the two short edges of the panel. This allows the panel to be folded into a 3-sided prism (each face will be 40 x 60 cm). Panels are usually scored by the distributor to facilitate folding, so this step may not be necessary.
2. Drill two pairs of holes into each panel using a ½ inch (1.3 cm) bit as indicat....

Results

In a large scale study, three artificial trap designs as well as girdled ash trees were deployed systematically, 10-20 m apart, across a newly infested 16 ha forested area with a very low density of EAB²⁵. Artificial trap designs tested included purple prisms baited with Manuka oil and suspended >3 m high from a branch in the canopy of ash trees, 3 m tall DD traps with two green panels, and DD traps with two purple panels supported by t-posts. Double-decker trap.......

Discussion

Both the design and placement of DD traps exploit the attraction of adult EAB beetles to specific shades of color and to light. The green prism on the top of the PVC pipe is most attractive to male beetles, who spend their life span feeding on ash leaves, as well as mating^32,36,38,39. The lower purple prism ensures traps are also attractive to female beetles³². Like male.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Light green corrugated plastic panel: 120 cm x 60 cm	Great Lakes IPM; www.greatlakesipm.com	IPM-EAB GR	All three surfaces of each prism need to be covered with clear insect trapping glue, even if the panels are pre-glued. Pre-glued panels are often not sticky enough to consistently capture or retain EAB beetles.  Other clear insect trapping glue products are available but are considerably more difficult to apply.
Light purple corrugated plastic panel: 120 cm x 60 cm	Great Lakes IPM; www.greatlakesipm.com	IPM-EAB  LP
Large cable tie (4): 60 cm with a 79 kg capacity	Cabletiesandmore.com; http://www.cabletiesandmore.com/cableties.php	CT-24-NU-100PK
Medium cable ties (4): 20 cm with a 22.7 kg capacity	Cabletiesandmore.com; http://www.cabletiesandmore.com/cableties.php	CT261
Small cable tie: 10 cm with a 8.2 kg capacity	Cabletiesandmore.com; http://www.cabletiesandmore.com/cableties.php	CT204
cis-3-hexanol pouch	Synergy Semiochemicals; http://www.semiochemical.com/html/buprestids.html)	3136	Lures used to bait DD traps consist of pouches containing cis-3-hexenol, a non-toxic compound present in ash leaves.  One pouch is attached to the lower edge of the top prism using a small cable tie.  Each pouch of cis-3-hexenol has a release rate of approximately 50 mg/day. Note that cis-3-hexenol is sometimes written as Z-3-hexenol.
Aphinity Hexenol	Sylvar Technologies
Lure GLV4 emerald ash borer	Chemtica, Heredia, Costa Rica
cis-3-hexanol pouch	WestGreen Global Technologies; http://www.westgreenglobaltechnologies.com/
Clear insect trapping glue	Hummert International; http://www.hummert.com/product-details/8196/pestick	01-3522-1
Histoclear II histological clearing agent	National Diagnostics; www.nationaldiagnostics.com	HS-202	Histoclear II will be needed to remove the sticky insect glue from suspect beetles.  Other histological clearing agents are available but may not remove the glue and some products dissolve plastic, an important consideration if plastic containers are used for soaking the beetles.
Histoclear II histological clearing agent	Great Lakes IPM; www.greatlakesipm.com	10011	Histoclear II will be needed to remove the sticky insect glue from suspect beetles.  Other histological clearing agents are available but may not remove the glue and some products dissolve plastic, an important consideration if plastic containers are used for soaking the beetles.
t-post: 1.5 m	multiple sources		A t-post (5 feet tall) (1.5 m) is used to support the PVC pipe.
post pounder	multiple sources		Use a post pounder to set t-posts into the ground. No additional support is necessary.
HDPE (high density polyethylene) PVC pipe : 3 m x 10 cm diameter	multiple sources
Forceps (rigid)	multiple sources		Forceps (tweezers) will be needed to remove suspect beetles from the traps. Rigid forceps work better than flexible forceps.
Latex gloves	multiple sources		Latex gloves are needed for applying the insect trapping glue to the prisms and for checking the traps to collect EAB beetles.
Baby oil or baby wipes	multiple sources		Baby oil or baby wipes are helpful for removing the trapping glue from hands and equipment.
Re-sealable plastic specimen bags: 5 cm x 8 cm	multiple sources		Small re-sealable plastic specimen bags are useful for collecting beetles from traps.  Each bag should be labelled, either with pre-made, adhesive labels or with soft felt pens.
Guides to help with distinguishing EAB from beetles native to North America are available on the national EAB website at www.emeraldashborer.info.