BIOLOGICAL CONTROL OF ANOPLOPHORA GLABRIPENNIS MOTSCH.: A SYNTHESIS OF CURRENT RESEARCH PROGRAMS

Authors: Smith, Michael; ZHONG-QI, YANG - ACADEMY OF FORESTRY CH; HERARD, FRANCK - EUROPEAN MONT FRANCE; Fuester, Roger; BAUER, LEAH - USDA USFS LANSING MI; SOLTER, LEELLEN - NATURAL HISTORY CHAMP IL; KEENA, MELODY - USDA USFS HAMDEN CT; D'AMICO, VINCE - USDA USFS HAMDEN CT

Submitted to: USDA Interagency Research Forum on Gypsy Moth and Other Invasive Species
Publication Type: Proceedings
Publication Acceptance Date: 3/20/2003
Publication Date: 4/20/2003
Citation: Smith, M.T., Zhong-Qi, Y., Herard, F., Fuester, R.W., Bauer, L., Solter, L., Keena, M., D'Amico, V. 2003. BIOLOGICAL CONTROL OF ANOPLOPHORA GLABRIPENNIS MOTSCH.: A SYNTHESIS OF CURRENT RESEARCH PROGRAMS. USDA Interagency Research Forum on Gypsy Moth and Other Invasive Species pp.87-91.

Interpretive Summary: The Asian longhorn beetle (ALB) is among a group of high-risk exotic woodboring insects native to Asia, specifically China and Korea. Within the U.S., ALB has been intercepted in 14 states, but established infestations are currently only known to exist in New York City and Long Island, NY, and in Chicago, Illinois. Utilizing the most effective method currently proven to limit its spread, approximately 5,286 and 1,509 infested trees have been located, cut and removed in the New York and Chicago infestations, respectively. Furthermore, ALB has thus far been reported to attack 18 hardwood tree species in 12 genera within these two U.S. infestations. Most notably among these are maples. In addition to the ability to attack and kill apparently healthy trees, ALB also structurally weakens trees, which poses a danger to pedestrians and vehicles from falling limbs or trees. Although quarantines and eradication programs exist in New York and Chicago, ALB possesses the potential for introduction into the urban, suburban and forest landscapes, particularly in eastern U.S. The estimated potential tree resources at risk to ALB attack in the U.S. range from 12 to 61% of the city tree population, with an estimated value of $72 million-$23 billion per city. The corresponding loss in canopy cover that would occur if all preferred hosts were killed ranges from 13-68%, with an estimated maximum potential impact of 34.9% of total canopy cover, 30.3% tree mortality (1.2 billion trees), and value loss of $669 billion. Therefore, efforts to develop biological control strategies that represent alternatives to the felling and chipping of infested trees were initiated within the past three years. Included among these are beneficial microorganisms, and insect predators and parasitoids. These strategies have two broad objectives. The first objective is focused on the development of mass rearing technologies, and inundative release and application technologies for these various biological control agents. The resulting technologies are intended to complement existing or other currently developing technologies (i.e. insecticidal controls) for use in the eradication program. The second objective is to develop technologies that could be utilized in managing ALB populations should eradication fail to succeed. This paper provides an update on the biological control research, with the exception of fungal pathogens, which is the subject of a companion paper in these proceedings.

Technical Abstract: Anoplophora glabripennis Motschulsky (Asian longhorn beetle) (ALB) is among a group of high-risk exotic woodborers native to Asia, specifically China and Korea. Within the U.S., A. glabripennis has been intercepted in 14 states, but established infestations are currently only known to exist in New York City and Long Island, NY, and in Chicago, Illinois. Utilizing the most effective method currently proven to limit its spread, approximately 5,286 and 1,509 infested trees have been located, cut and removed in the New York and Chicago infestations, respectively, as of May 2001. Furthermore, A. glabripennis has thus far been reported to attack 18 deciduous tree species in 12 genera within these two U.S. infestations. Most notably among these are maples (Acer spp.). Furthermore, based upon field data from nine U.S. cities, national tree cover data and proposed host preference of A. glabripennis, the estimated potential tree resources at risk to A. glabripennis attack range from 12 to 61% of the city tree population, with an estimated value of $72 million-$23 billion per city. The corresponding loss in canopy cover that would occur if all preferred hosts were killed ranges from 13-68%, with an estimated maximum potential impact of 34.9% of total canopy cover, 30.3% tree mortality (1.2 billion trees), and value loss of $669 billion. Therefore, efforts to develop biological control strategies that represent alternatives to the felling and chipping of infested trees were initiated within the past three years. These strategies have two broad objectives: (1) development of mass rearing and mass production technologies, coupled with inundative release and application technologies; and (2) development of technologies that could be utilized in managing A. glabripennis populations should eradication fail to succeed. Included among the biological control agents being considered are nematodes, Bacillus thuringiensis, microsporidia, and predators and parasitoids. Results to date include: (1) Entomopathogenic nematodes may offer an alternative and/or complementary method for the control of ALB, specifically targeting the larval and or pupal stages. Therefore, four entomopathogenic rhabditoid nematode species, Steinernema carpocapsae, Heterorhabditis bacteriophora, H. indica, and H. marelatus, were tested for their ability to kill and reproduce in larvae of the ALB. The ALB larvae were permissive to all four species but mortality was higher and production of infective juveniles (IJ) was greater for S. carpocapsae and H. marelatus. The greatest challenge facing the use of nematodes to control ALB within trees is development of effective delivery technology. (2) Bacillus thuringiensis (Bt) was evaluated as a microbial insecticide against larval and adult ALB. Results to date have not been promising. (3) A new microsporidium isolate from ALB larvae was collected in Henan Province, China (December 2001), but it is as yet unidentified. Infection prevalence of larval samples was ca. 2% (n=97). (4) Finally, in regard to insect predators and parasitoids, two approaches are being utilized in these efforts: (1) evaluation of natural enemies known to attack ALB in China; and (2) evaluation of possible new associations between ALB and natural enemies of other cerambycids in China, Europe and North America. Efforts to identify and evaluate congeners of ALB natural enemies native to China are also underway. However, in order to focus efforts on those natural enemy species with a greater probability of providing biological control of ALB, selection and prioritization of these natural enemies are based largely upon the relatedness of their respective longhorn beetle hosts to ALB at three levels: (1) phylogenetic relatedness; (2) ecological relatedness (e.g. climate; habitat; host tree species and condition); and (3) behavioral relatedness (e.g. larval feed