2013 Annual Report
1a.Objectives (from AD-416):
1. Investigate the behavioral ecology of host selection and colonization, and the process of invasion of invasive insect pest species of natural ecosystems, including Asian Longhorned Beetle (ALB), and other invasive species such as Citrus Longhorned Beetle (CLB).
2. Discover and identify exotic natural enemies of the Asian Longhorned Beetle (ALB) and other invasive species such as Citrus Longhorned Beetle (CLB) of natural ecosystems, and evaluate their host specificity, host searching ability and efficacy as potential biological control agents within the United States.
3. Discover and identify native natural enemies of the Asian Longhorned Beetle (ALB) and other invasive species such as Citrus Longhorned Beetle (CLB), and evaluate their biology, ecology and efficacy as biological control agents within the United States, including development of surrogate rearing systems for natural enemies, as needed for APHIS eradication programs.
1b.Approach (from AD-416):
1.1.a. We will conduct a series of a series of field experiments to determine the distance A. glabripennis are attracted to Acer mono (Painted Maple). Potted A. mono saplings will be systematically positioned at varying distances from adult beetle infested trees in ALB infestations. Adult beetles will be collected, uniquely marked and released onto infested trees at predetermined distances from the potted A. mono, which will then be checked daily and the marked beetles identified and counted, and referenced to the position of release as a measure of attractive distance (attractive radius). Effects of positioning A. mono within vs. adjacent to infested landscapes will be evaluated in closed canopy, patch/clumped and open canopy landscapes to optimize detection of ALB using A. mono sentinel trees and provide landscape-specific guidelines for implementation in the U.S., Canada and Europe. 1.1.b. We will conduct a series of field experiments to develop an artificial lure for detection of adult ALB. We will determine the relative attraction of ALB to: (1) traps baited with different formulations and dosages; (2) trap position within host trees; (3) trap position within landscapes; and (4) method of deployment. Choice experiments will be conducted using a randomized complete block design, and treatments within block will be rotated daily. Traps will be checked daily, number and gender of each beetle recorded, removed and preserved. In addition, we will conduct a series of field experiments to determine the distance at which adult A. glabripennis beetles are attracted to the optimized artificial lure (see approach outlined above for Acer mono). 1.2. We will conduct field studies of the process of population spread and host colonization in invasive ALB populations in North America and Europe. We will use dendrochronology methods to date signs of attack on infested trees within different landscapes of two ALB infestations (Toronto, Canada; Treviso, Italy), thereby providing the timeline of attack and emergence. We will use GPS methods of infested trees to provide the spatial scale of population spread. Collectively, this approach will allow us to reconstruct the process of population spread and to development of predictive spatiotemporal models of population spread and host colonization on which to base implementation of a wide range of adaptive management strategies for existing introductions, and for restricting establishment, proliferation and spread of future introductions. 2. We will combine the geographic distribution of epidemic ALB populations with that of mixed deciduous forests to predict the geographic and host range of ALB, specifically focusing on noninvasive populations within natural ecosystems in South Korea and China. We will conduct foreign exploration to identify natural enemies of ALB within natural ecosystems and evaluate host specificity and efficacy as biological control agents of ALB. 3. In natural forests, we will identify native woodborers and associated native natural enemies of maple, and evaluate the later as biocontrol agents of ALB. We will identify native natural enemies parasitizing ALB within infestations in the U.S.
Interception of invasive species prior to entry into new countries requires effective detection methods. Should they elude interception, their detection while confined to small areas is paramount to limiting expansion of infested areas and minimizing potential spread to previously unaffected areas. Should they become permanently established, biological control is key for preventing widespread or permanent loss of high value natural resources. This project focuses on two invasive insect pests from Asia, the Asian Longhorned Beetle (ALB) and Citrus Longhorned Beetle (CLB), both of which kill over 35 tree species in urban and residential areas, parks and natural forests. Progress in this project emphasizes development of: (a) technology for detecting adult ALB and CLB; (b) technology for detecting the concealed ALB and CLB larvae feeding in the heartwood of trees; (c) models for predicting dispersal and population spread of adult ALB and CLB, critical for focusing survey, detection and control efforts where most effective; (d) models for predicting when adult ALB and CLB emerge from infested trees, critical for focusing survey, detection and control efforts when most effective, e.g. when to release of natural enemies for biological control; and (e) natural enemies (e.g. parasitic wasps) used for biological control of ALB and CLB.
We evaluated the attraction of adult CLB to Sugar Maple and its effectiveness as a sentinel tree for early detection of CLB. Young trees were systematically planted within CLB infestations in northern Italy. Trees were inspected daily for the presence of adult CLB and its signs of attack. Results indicated that Sugar Maple is highly attractive to CLB, with significant potential for early detection of CLB. We compared the effectiveness of three acoustic sensors to detect sounds produced by ALB larvae feeding deep within infested logs or trees. One of each sensor was simultaneously attached to a single log containing ALB larvae, and recordings made while systematically varying the distance between the sensors and larvae. Results showed one sensor more effectively distinguished ALB feeding sounds from background noise, and detected the feeding sounds at greater distances from the ALB than the other two sensors. Potential commercialization is under evaluation. We explored for wasp species parasitizing woodborers that naturally occur in U.S. forests, and then conducted studies to determine which of the wasp species successfully parasitize ALB. Within natural forests, we identified maple trees natural infested with woodborers. Infested trees were cut, logs collected, returned to the lab, held in cages and check daily for wasps and parasitized woodborers. Adult wasps were then caged together with logs infested with ALB and observed daily for parasitism of ALB. Two wasp species were found to parasitize and complete development on individual ALB larva, and subsequently identified. Results from evaluation of their biology and rates of parasitism of ALB indicate that the two species, particularly when used in tandem, may provide highly effective biological control of ALB.
Early detection of the Asian Longhorned beetle. Asian Longhorned Beetle (ALB), Anoplophora glabripennis, native to China, is considered among the world’s most devastating invasive species of hardwood trees, especially maples, and could potentially kill over 30% of all trees in areas of eastern U.S., representing a threat of approximately $670 billion. Eradication of ALB requires the early detection and rapid response for preventing the initial establishment of infestations and their potential spread. In cooperation with University of Delaware (UD), ARS researchers at Newark, Delaware developed two models to meet these needs for predicting where to focus and intensify survey efforts for early detection of ALB , and for predicting the time during which to focus and intensify survey efforts for early detection of ALB. Predictions from these models currently serve as the basis for determining when to implement and where to focus survey, treatments and other adaptive management strategies. These science based tools have reduced the cost and improved the effectiveness of early detection of ALB in existing infestations and have been adopted by APHIS, state and local agencies, as well as internationally, for survey and early detection of new infestations. Collectively, implementation of these tools has resulted in the successful eradication of ALB in Chicago, Illinois (2008), Hudson County, New Jersey (2008), Islip, New York (2011), Middlesex and Union Counties, New Jersey (2013) and Toronto, Canada (2013).