2012 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.
Continued to assess potential invasiveness of the Asian Longhorned Beetle (ALB) and Citrus Longhorned Beetle (CLB), and in collaboration with University of Vermont and New Hampshire Department of Agriculture, field studies were conducted in VT, NH and NY to evaluate its growth factors as indicators of potential invasiveness. In cooperation with Voltree Power Inc., Schertler, Ltd. and ARS-Center for Medical, Agricultural, and Veterinary Entomology, evaluated the sensitivity of three acoustic sensors to detect sounds produced by immature ALB feeding within infested logs. Results indicate one sensor is most effective. In cooperation with Canadian Forest Service and University of Padova, continued to develop and optimize models for predicting ALB dispersal and spread in urban, residential, natural forests and other areas vulnerable to establishment by ALB. Preliminary results indicate that population abundance, host composition and relative abundance and landscape fragmentation are key factors determining the rate and direction of spread. In cooperation with University of Delaware, initiated studies to develop degree day models of adult ALB life expectancy, and evaluated the integration of these models with the degree day model of ALB emergence. This resulted in timely and accurate forecasting of the presence and relative abundance of adult ALB, which we updated weekly and distributed to stakeholder and posted to our webpage. In collaboration with University of Delaware, we continued to identify the geographic and host range of ALB and CLB in Asia. Results have identified regions in China likely harboring effective parasitic wasp for biological control of ALB and CLB. In collaboration with ARS-European Biological Control Laboratory, exploration for natural enemies of ALB and CLB in China was initiated. Predictions from our degree day models of ALB and CLB and identification of the geographic and host range of ALB and CLB in China were used to focus exploration for natural enemies of ALB and CLB by EBCL. An egg parasitoid of CLB was discovered. Continued exploration and evaluation of parasitic wasps native to US forests for biological control of ALB. Discovered two parasitic wasps successfully parasitize ALB larvae within infested logs. In collaboration with ARS-Systematic Entomology Laboratory, both wasps were identified. Results from evaluation of their biology and rates of parasitism of ALB indicate strong potential for biological control of ALB. Most important, the species appear to be complementary, potentially most effective under different ALB population levels.
Models for predicting emergence and abundance of Asian Longhorned Beetle (ALB). 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. The adaptation of ALB to climatic conditions from southern Canada, across the US and into Mexico significantly compromising early detection of and rapid response to ALB infestations, which rely heavily on predicting when to implement survey and control methods under widely varying climatic conditions. In cooperation with University of Delaware (UD), ARS researchers at the Beneficial Insects Introduction Research Unit at Newark, Delaware developed degree day models for predicting adult ALB emergence from infested trees and estimates of how long adult beetles survive. Using 2012 temperature data and 10 day forecasts from high risk locations spanning 13 states from ME to MN, ARS researchers developed predictions of when adult beetles first emerge; the period of time when adult beetles attack trees; and when adult beetles are most abundant. Predictions were updated weekly, posted online, and distributed to key stakeholders, including federal, state and city agencies, universities, citizen groups and private companies. The predictions proved to significantly impact implementation of survey and monitoring in 2012 by advancing their implementation ca. 2-3 weeks earlier than would otherwise occurred. Results from these models are also currently used in timing the deployment of attractants for early detection of adult beetles, and will be used to time the release of natural enemies for biological control.