A Case Study: The Asian Longhorned Beetle (Anoplophora glabripennis Motschulsky)
Gary J. Torrisi
Instructor: Dr. John Foster
November 1, 2009
In the 1990's it has been estimated that over 400 non-native, exotic forest pests have established breeding populations in the United States (Haack, 2003). Since that time new exotic species are discovered annually (Haack, 2003). One recent arrival is the Asian longhorned beetle, Anoplophora glabripennis (Coleoptera: Cerambycidae) first discovered in New York City in 1996 (Cavey et al., 1998).
In March 1997 the United States Department of Agriculture Animal and Plant Health Inspection Services (USDA APHIS) implemented a federal quarantine to regulate the movement of host material that might harbor life stages of A. glabripennis. Federal and university researchers have since conducted numerous studies focusing on new knowledge and technologies that might prove useful in eradicating this invasive species. Studies are addressing A. glabripennis biology, taxonomy, rearing, survey, control, economic impact, regulatory issues, and public education (Haack, 2003).
The estimated losses are based upon the beetle's ability to kill a wide range of tree species. Threats to the maple sugar industry, a 38.4 million dollar value in 2002, the fall foliage tourist industry where one million tourists generate a billion dollar industry; and public parks, and residential yards and tree lined streets with losses in the millions of dollars just in New York City and Chicago alone (Campbell, 2008). If left unchecked, initial estimates placed damages around 669 billion dollars (US) (http://www.uvm.edu/albeetle/research/index.html).
In 1996 there were no known pesticides or natural enemies to control the beetle as well as no satisfactory trap to detect the beetle's presence (Milius, 1999). The only recommendations provided for at the onset of discovery was quarantine the area, cut down the trees, chip, and burn the infested trees.
This case study has been designed to provide and update information on Anoplophora glabripennis. Included in this case study is a review of the history of the infestation into the United States, current knowledge of the biology, and life history. In addition, a review of research progress in management strategies, and innovated technology that may prove beneficial in eradication programs.
History of United States Infestation
Anoplophora glabripennis is native to Eastern China, Japan, and Korea. Known as a hardwood borer, it attacks a variety of living trees. Early reports suggest that the beetle shows a preference for maple (Acer) and horse chestnut (Aesculus hippocastanum) in the United States and Norway maple (A. platanoides) in Austria and poplar (Populus), willow (Salix), elm (Ulmus), mulberry (Morus), and black locust (Robinia pseudoacacia) in its native countries (Zhang et al., 2002).
The Asian longhorned beetle has been unintentionally introduced into the United States and Europe via untreated wooden packing and crating material probably from China (Zhang et al., 2002). Experts believe that the beetle hitch-hiked into the United States in the early 1990's (USDA APHIS Program Aid No. 1655; http://www.dnr.state.oh.us/health/asianlonghorned/tabid/5197/Default.aspx). This insect was first discovered in New York City in August 1996 (Milius, 1999, Haack, 2003). Residence of the Greenpoint section of Brooklyn noticed an oddity in tree damage in maples and horse chestnuts and reported these observations to a forestry inspector (Milius, 1999). Rhichard Hoebeke, assistant curator of Cornell University's insect collection was the first to recognize it as Anoplophora glabripennis, a well known pest of Southeastern Asia (Milius, 1999). In September 1996 beetles were observed in Amityville, New York. They may have hitch-hiked from Brooklyn through a tree pruning company that moved cut wood from Brooklyn. A year later beetles appeared in Lindenhurst, New York.
Two years later (1998), a Chicago man identified the beetle crawling out of his firewood (Milius, 1999). Subsequent investigations found infested trees in Chicago's Ravenwood District and nearby communities of Addison and Summit (Milius, 1999). In 1999, yet another hotspot was uncovered in the Bayside area of Queens. In October 2002 A. glabripennis was found in Jersey City, New Jersey along with infestations in Toronto, Canada (Haack, 2003; Campbell, 2008). In 2001, a breeding population of beetles was discovered in Austria (Haack, 2003).
On a brighter note, quarantine status was lifted in Illinois in July 2006 since no beetles were found in the area (http://www.uvm.edu/albeetle/research/index.html).
In 2007 the beetle has shown up in Prall's Island and Staten Island a harbor area between New York and New Jersey (Campbell, 2008). The latest heavy infestation of great concern was discovered in Worcester, Massachusetts in August 2008 and a re-occurrence of an infestation in the Chicago area. (Campbell, 2008). In October 2009 the U.S. Department of Agriculture inspectors found the beetle in neighboring West Boylston, Massachusetts (http://www.courant.com/news/connecticut/hcwoodchopping1013.artoct13,0,4875274.story). As of 2009 Asian longhorned beetles have been detected in Austria (2001), France (2003, 2004, 2008), Germany (2004, 2005), and Italy (2007) (http://www.uvm.edu/albeetle/research/index.html).
The Asian longhorned beetle has been found in at least 14 states and over two dozen scattered sites (http://www.dnr.state.oh.us/health/asianlonghorned/tabid/5197/Default.aspx). Additionally, the beetle has been found in the solid wood packing and crating material in Ohio however, infestation in living host trees has not been detected (http://www.dnr.state.oh.us/health/asianlonghorned/tabid/5197/Default.aspx).
If the urban outbreaks of the Asian longhorned beetle are not eradicated, the beetle is likely to spread to North American forests. If so, it has the potential to alter ecosystems across the continent changing dominant species composition and age structure in hardwood forests from New England to the Great Lakes and into the majority of Canada's hardwood forests as well (Campbell, 2008).
Biology and Life History of the Asian Longhorned Beetle
There are approximately 30,000 species of wood-boring, longhorned beetles in the world of which some 2000 are found in the United States (Milius, 1999). The genus Anoplophora contains 36 species often identified by varieties in their elytra patterns (Haack, 2003). In the United States, a number of trees have already been identified as suitable hosts for A. glabripennis. The following tables summarize the host trees infected by ALB in the US as of February 2008 by the USDA APHIS PPQ new post guidelines. Surveys indicate that infected trees exhibit premature yellowing or loss of leaves as larvae tunnel into the cambrium and xylem of the tree (Zhang et al., 2002; http://www.dnr.state.oh.us/health/asianlonghorned/tabid/5197/Defaiult.aspx).
Preferred host in US Occasional host in US Genus Common Name Genus Common Name Acer Maple, boxelder Albizia Minosa, silk tree Aesculus Horsechestnut, buckeye Fraxinus Ash (especially green) Betula Birch Platanus London plane tree Salix Willow Populus Poplar Ulmus Elm Sorbus European mountain ash
Signs of infestation include dime size, round holes with smooth edges, oozing sap, oviposition sites, and piles of frass (waste and sawdust) at the base of trees and/or branch crotches (http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/alb_response_guidlines.pdf; http://www.dnr.state.oh.us/health/asianlonghorned/tabid/5197/Defaiult.aspx).
During mating, males remain around the females for many hours guarding their mates and protecting their established territory (Milius, 1999). Adult males will actually bite off the leg or antennae of an intruding male opponent in defense of their territory (Milius, 1999).
There is not much data on flight and predictable range extension. Reports indicate a flying range from the initial tree host to be 300 to 400 meters and possibly further if wind aided (Milius, 1999; (http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/alb_response_guidlines.pdf). In an attempt to record the dispersal rate of infestations it has been noted that 96% of A. glabripennis adults dispersed within 200 m, and 99% of A. glabripennis dispersed within 400 m of their larval host tree(Haack, 2003). Consequently these beetles do not appear to spread quickly but have been aided unintentionally through the movement of firewood (http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/alb_response_guidlines.pdf). Migration seems to depend upon access to suitable tree hosts attacking a single host tree (http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/alb_response_guidlines.pdf). Research is currently testing flight capabilities using fluorescence markers and radio transmitters to collect valuable date (Milius, 1999).
There are no natural predators or parasitoids in the United States or Canada and few exist in China (http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/alb_response_guidlines.pdf). There exists a cooperative effort on the part of both governments in collecting data, investigating biological controls, and sharing of past information in an effort to control or exterminate this pest. Trees of any age are attacked but preference for trees 4" in diameter or larger dominate the beetles behavior (http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/alb_response_guidlines.pdf; http://www.dnr.state.oh.us/health/asianlonghorned/tabid/5197/Default.aspx).
The adult external morphology is characterized by size and color markings. Adults are 1- 1 1/2 inches long, shiny black with white spots. They are adorned with a pair of curved, black and white banded antennae that extend beyond the length of the adults body.
The Asian longhorned beetle is univoltine where unlike so many other longhorned beetles that reproduce every 2-4 years (http://www.dnr.state.oh.us/health/asianlonghorned/tabid/5197/Defaiult.aspx). Females spend most of their 42 days (mean data) of adult life ovipositing eggs one at a time. Females chew a groove just under the tree bark and inject a single egg the size of a rice grain. Females are capable of depositing 35 to 90 eggs in a lifetime. Under laboratory conditions, average fecundity ranged from 51-93 eggs per female and average adult longevity ranged from 73-104 days (Haack, 2003). Eggs hatch in 10-15 days and begin to eat their way into the soft cambium layer (containing phloem tissue) of the tree. The larvae then molt twice prior to chewing their way into the water vessels (xylem tubes) of the heartwood. Upon arrival into the heartwood the larvae remain during the winter months and continue eating. In the spring, they pupate and the emerging adults begin to bore their way out of the tree through round tunnels during the months of May through July. The adults continue to feed on small twigs for several days. Mating occurs as early as the second day after emergence. All adults die in the fall. Approximately nine months are spent within the tree host and a cooler period is an apparent abiotic condition needed prior to pupation ( Milius, 1999; Haack, 2003; http://www.dnr.state.oh.us/health/asianlonghorned/tabid/5197/Defaiult.aspx; http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/alb_response_guidlines.pdf).
Survey and Detection Methods
Since A. glabropennis spends much of its life buried deep into its host tree, alternative techniques are employed to detect infestations.
Visual inspections reveal the round, smoothed edged exit holes made by the emerging adults. Ground observations are conducted by federal and state government inspectors, interest groups, and conservation organizations in addition to local residence sighting adult beetles and reporting bore holes. Recently, acoustical detectors are being used to supplement visual inspection by picking up feeding sounds within 6-7 meters of its source (Haack, 2003). The use of bucket trucks allows inspectors to reach host trees far above the ground. In tight areas where bucket trucks are inaccessible, firefighters, professional tree climbers, and smoke jumpers are employed to survey the upper most portion of a tree (USDA APHIS Program Aid No. 1655)..
A number of research projects are underway. To date, few researchers have yet to publish their findings, however, areas of interest include experimentation with traps using pheromones as lures, similar to the successful strategy reported in the gypsy moth and Japanese beetle eradication projects of the past (USDA APHIS Program Aid No. 1655). The use of plant-host odors to supplement visual inspection and as an aid in locating infected trees and potential tree hosts is being studied. Efficacy of insecticides delivered directly to infected trees through trunk injections, soil treatments, and bark sprays are being investigated (Zhang et al., 2002; Haack, 2003; http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/alb_response_guidlines.pdf). Microwave irradiation of wood packing material especially in quarantine treatment centers at points of departure and points of entry are being used effectively (Fleming et al., 2002). Additional research involving heat treatment, fumigation with methyl bromide, mass rearing of the beetle for research purposes, and the possibility of releasing sterile adults are collectively being pursued as potential eradication techniques if current treatments fail (Haack, 2003).
Work continues in both China and the United States on a variety of predators, parasitoids, and entomopathogens (Haack, 2003). The effectiveness of nematodes, various species of fungi, microsporidia, Bacillus thuringiensis toxins, and a close look at Dastarcus longulus (Coleoptera: Colydiidae) and Scleroderma guani (Hymenoptera: Bethylidae) the two primary natural enemies of A. glabripennis in China (Haack, 2003).
APHIS has set a goal of eradication of breeding populations established in the United States. The best way to fight the Asian longhorned beetle is through exclusionary programs both here and at the source. In order for these goals to be met, total cooperation of all involved is required for success. Through research and public input, urban infestations have been isolated, knowledge of the beetle's biology and life history is continually updated, and innovative techniques applied toward survey and treatments of infestations are being tested. In addition, APHIS has also put together a program of educational outreach through multi-media channels. Educating the public, holding informational meetings, and updating information disseminated through various media are an important part of the management program.
The geographical extent and likely path of invasion into North America is unknown (Peterson et al., 2004). What scientists warn us about is that if this invasive pest is not controlled the economic losses will surge into the hundreds of billions of dollars.
Cavey, J. F., E. R. Hoebeke, S. Passoa, and S. W. Lingafelter. 1998. A new exotic threat to North American hardwood forests: an Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae). I. Larval description and diagnosis. Proc. Of Entomol. Soc. Wash. 100 : 373-381.
Fleming, M. R., K. Hoover, J. J. Janowiak, Y. Fang, X. Wang, W. Liu, Y. Wang, X. Hang, D. Agrawal, V. C. Mastro, J. E. Shield, and R. Roy. 2002. Microwave irradiation of wood packing material to destroy the Asian longhorned beetle. Forest Prod. J. 52 : 1-7.
Haack, R. A. 2003. Research on Anoplophora glabripennis in the United States. Nafhrichtenbl Deut. Pflanzenschtzd. 55:68-70.
Ludwig, S. W. L. Lazarus, D. G. McCullough, K. Hoover, S. Montero, and J. C. Sellner. 2002. Methods to evaluate host tree susceptibility to the Asian longhorned beetle, Anoplophora glabripennis. J. Environ. Hort. 20: 175-180.
Milius, S. 1999. Son of long-horned beetles. Sci. News. 155: 380 - 382.
Peterson, A. T., R. Scacheti-Perciro, and W. W. Hargrove. 2004. Potential geographic destruction of Anoplophora glabripennis (Coleoptera: Cerambycidae) in North America. 151: 170 - 178.
(USDA) U. S. Department of Agriculture. 2009. USDA APHIS Program Aid No. 1655. USDA, Beltsville, MD.
Zhang, A. J. E. Oliver, J. R. Aldrich, B. Wang, and V. C. Mastro. 2002. Stimulatory beetle volatiles for the Asian longhorned beetle, Anoplophora glabripennis (Motscholsky). Z. Naturforsch. 57 : 553 - 558.
World Wide Web
Asian Longhorned Beetle. 2009. http://www.dnr.state.oh.us/health/asianlonghorned/tabio/5197/Default.aspx
Asian Longhorned Beetle Research. http://www.uvm.edu/albeetle/research/index.html
Asian Longhorned Beetle Threatens State's Forest. 2009. http://www.Courant.com/news/connecticut/he-woodchopping1013,artect13,0,4875274.story
Campbell, F. 2008. Gallery of pests: Pests & pathogens not too widely spread. http://www.invasive.org/gist/products/gallery/anogl1.html
(USDA) U.S. Department of Agriculture. 2008. New pest response guidelines- Asian longhorned beetle, Anoplophora glabripennis. http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/alb_response_guidlines.pdf