INTEGRATED PEST MANAGEMENT OF THE REDBAY AMBROSIA BEETLE, AN EXOTIC AND NEWLY INTRODUCED FOREST SPECIES IN FLORIDA

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: MCINTIRE-STENNIS
• Reporting Frequency: Annual
• Accession No.: 0221111
• Project Start Date: Jan 1, 2010
• Project End Date: Dec 31, 2014
• Program Code: [(N/A)]- (N/A)

Recipient Organization
FLORIDA A&M UNIVERSITY
(N/A)
TALLAHASSEE,FL 32307

Performing Department
Agricultural Research

Non Technical Summary
A non-native insect, the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), has been recently introduced into forests of the southeastern United States. The beetle carries a fungus which is lethal to several plants in the family Lauraceae, particularly redbay (Persea borbonia) and sassafras (Sassafras albidum) in coastal forest areas of Georgia, South Carolina, and Florida. Several other plants including the economically important avocado are threatened. It is not feeding by the beetle that causes most damage, but rather an associated fungus which can cause the death of an infected plant in as little as eight weeks. The beetle and its associated fungus have spread rapidly and created an epidemic through natural spread and accidental introductions by humans, resulting in very high mortality rates of redbay trees along the Atlantic coast from South Carolina to Florida. In spite of recent research efforts, there are no control measures for this pest and very little is known about its biology and its interactions with various host trees. A better knowledge of the biology, population dynamics, and host associations should provide useful insights in the development of sustainable management strategies. The objectives of this project are to learn more of the biology and population dynamics of the beetle, to collect and characterize the pathogenic fungi carried by the beetle, to collect and characterize associated fungal pathogens which might be useful in control, to evaluate toxicity of pesticides which might be used, and ultimately to develop an environmentally friendly and sustainable pest management strategy. The work will be done at Florida A&M University but in collaboration with other researchers concerned with forestry, agriculture, and invasive pests (USDA Forest Service, USDA/ARS, Florida Department of Agriculture & Consumer Affairs (Forest Service and Division of Plant Industry). Multiple field collections of the redbay ambrosia beetle from infested trees will be conducted in counties of North Florida and Southern Georgia in order to supplement distribution records, obtain specimens, and examine different rearing techniques in the laboratory. The beetles will also be reared in logs at selected sites already infested. The beetles will be studied for susceptibility to standard pesticide and fungicide treatments. Because fungi are the major problem, we will extract and characterize the fungal pathogens and examine the possibility of using other pathogenic fungi to reduce beetle populations or to compete with or replace the disease-causing fungi. Much of this is labboratory work and, based on preliminary results in the laboratory, we intend to proceed to field trials with pesticides and fungi that attack insects. Results will be disseminated in peer-reviewed publications and at professional meetings. In collaboration with other research institutions, we hope to contribute to the control of the redbay ambrosia beetle and the conservation of the natural forest ecosystem.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
123	0699	1102	50%
123	0699	1130	50%

Knowledge Area
123 - Management and Sustainability of Forest Resources;

Subject Of Investigation
0699 - Trees, forests, and forest products, general;

Field Of Science
1130 - Entomology and acarology; 1102 - Mycology;

Keywords

ipm

redbay ambrosia beetle

invasive species

Goals / Objectives
The invasive redbay ambrosia beetle has recently been introduced to forests of the Southeastern United States and poses a threat to the native forest ecosystem. The overall goal of this project is to develop an integrated approach to control this beetle. The specific objectives include 1. Study of biology and dynamics of populations of the redbay ambrosia beetle. 2. Collection and identification of field collected fungal pathogens from live and dead ambrosia beetles as well as its symbiotic fungi using DNA fingerprinting techniques. 3. Evaluation of the toxicity of selected insecticides to be used against the redbay ambrosia beetle and fungicides to be used against its symbiotic fungal isolates. 4. (a) Evaluation of the pathogenicity and virulence of biocontrol fungi Metarhizium anisopliae, Beauveria bassiana and Paecelomyces farinosus against the redbay ambrosia beetle as well as the most promising fungal pathogens isolated from field collected beetles; (b) Evaluation of the pathogenicity of these biocontrol fungi against the symbiotic fungi of redbay ambrosia beetle. 5. Development of an environmental friendly and sustainable management strategy for the redbay ambrosia beetle. Results of the study should provide more information on basic biology of the beetle and its distribution in the Southeast in order to find new approaches and natural control agents which might be used in management or control. A better understanding of the fungal pathogen is critical. Unique to this project is the attempt to isolate existing fungal pathogens which might compete with the fungal pathogens carried by the beetle, or possibly provide direct control of the beetle as part of a management strategy. Efficacy of existing chemical controls will also be evaluated. The project is a collaborative relationship on the FAMU campus between this college, the Department of Biology and Dr. L. Latinwo (Molecular Biologist) who will assist in the studies dealing with molecular genetic aspects of the project and the Environmental Sciences Institute (Dr. M. Abazinge). Mr. Ted Willis (USDA Forest Service) will provide leadership and communication with stakeholders and with the public. The project will support one graduate student who will provide original research results leading to improved management of the pest. It will also strengthen the existing partnerships and cooperative efforts between FAMU, USDA-Forest Service, and Florida Department of Agriculture and Consumer Services, Division of Forestry and Division of Plant Industry (DPI) and the Cooperative Agricultural Pest Survey Program at DPI which is also concerned with the redbay ambrosia beetle and other invasive species. At the conclusion of this project, strong cooperative linkages will serve as useful and reliable foundations for future ventures.

Project Methods
Field collections from infested trees will be made in counties where redbay ambrosia beetles are established. Rearing techniques will use one of two standard artificial diets. Each diet tube will be inoculated with a single female which will produce fungal galleries and adult progeny. Beetles can also be reared in logs at infested sites. To assess the dynamics of adult beetle populations, ten healthy trees will be wounded and an attractant positioned in the wound. A piece of heavy gauge steel wire will be wrapped around each tree and shaped into a hook so sampling traps can be hung directly above each site. To isolate fungal pathogens, live beetles and cadavers will be collected. The insects will be surface-sterilized and plated on Sabouraud Maltose Agar and Yeast to investigate potential pathogenic agents. Fungal symbionts will be isolated and incubated on a malt extract-based media. Cultures will be harvested and identified using molecular genetic techniques to determine the different isolates of symbiotic fungi. Fungal samples collected from the beetle will be subjected to DNA isolation, purification and then DNA sequencing for identification. We will also investigate competition between the fungal symbionts and pathenogenic fungi such as Metarhizium, Beauveria, Paecelomyces, and other promising fungal isolates. Disks of mycelial cultures of each competing pair will be randomly placed in a 4X 5 grid on a malt extract agar plate in various ratios. Differential competition will be determined by comparing mean area occupied versus initial inoculum proportion. Pesticide screening will use technical-grade samples as supplied by the manufacturers. These will include two neonicotinoids, emamectin benzoate and the fungicide phosphonate. Relative toxicity or resistance will be analyzed using the procedure of Kanga and Plapp (1992). The neonicotinoids will also be mixed into the diet and fed to adult and larval beetles. For field studies of efficacy, 4 blocks of host trees will be established, each with 10 similar size trees. Two trees within each block will be randomly assigned to one of the 5 treatments. Insecticide-treated and non-treated trees will be monitored at 7 d intervals for three months, new galleries will be circled, their presence monitored and new attacks will be recorded. The neonicotinoids and the fungicide phosphonate will be applied as trunk injection, trunk spray or soil drench with or without the surfactant Pentra-Bark. Trunk injection will include imidacloprid, emamectin and phosphonate and trunk spray will include Pentra-bark with either imidocloprid or dinotefuron. Statistical analyses of concentration-mortality data will be subjected to probit analysis to obtain the lethal doses. Differences among populations in response to insecticides and dose-mortality responses of fungal isolates will be considered significant if the 95% confidence levels of the LD50s do not overlap (Robertson and Preisler 1992). Based on susceptibility of redbay ambrosia beetle to pesticides and fungal pathogens, a potential integrated management strategy will be developed.

Progress 01/01/10 to 12/31/14

Outputs
OUTPUTS: A non-native insect, the redbay Ambrosia beetle, Xyleborus glabratus Eichhoff was discovered in the United States in 2002. This invasive beetle pest vectors the laurel wilt virus which has been responsible for extensive mortality of redbay in the coastal plain counties of the Southeast and threatens forest, landscape and agricultural trees of the family Lauraceae. The specific objectives include: 1) study of biology and dynamics of populations of the redbay ambrosia beetle and other potential destructive invasive alien species; 2) collection and identification of symbiotic fungi and field-collected fungal pathogens from live and dead ambrosia beetles using DNA fingerprinting techniques; 3) evaluation of the pathogenicity and virulence of commercial biological control agents against the ambrosia beetle and its symbiotic fungi; 4) development of a sustainable management strategy for the redbay ambrosia beetle. Expected outputs include: knowledge of the biology and dynamic of Ambrosia beetle pest species, better understanding of host-plant interactions, identification of novel and highly pathogenic fungal isolates for the control of invasive species, availability of pest management tools for protection of redbay and other Lauraceae species. Completed outputs include: (i) identification and listing of potential destructive Ambrosia beetles that threaten the environmentally sound management of forest natural resources in Florida, (ii) enhanced stakeholder knowledge of potential invasive forest species, and (iii) creation of strong and reliable collaborative linkages with stakeholders and the Florida Department of Plant Industry. Findings from the project are being disseminated through a variety of avenues, including websites, and newsletters. Project achievements are also available to the stakeholders and public through national meetings and conferences, extension bulletins, brochures, seminars, and workshops. Scientific findings will be reported in referred journals (Journal of Economic Entomology, Journal of Invertebrate Pathology, and Florida Entomologist). PARTICIPANTS: The PI (Dr. Lambert Kanga) and Co-PIs (Dr. Moses Kairo and Dr. Oghenekome Ononkpise) design, implement and manage the daily research activities of the proposed project; they are instrumental to the success of the project. A graduate student (Miss Latasha Tanner) is responsible for day-to-day field management and data collection, and assists undergraduate students in managing specific projects. Undergraduate students have provided assistance with this project during periods of intensive field evaluations and sampling of pest populations. The project brings together a wide range of expertise and resources to develop a management strategy for the redbay ambrosia beetle. It has established strong and reliable collaborative linkages with the US Forest Service, the Florida Department of Plant Industry, the Cooperative Agricultural Pest Survey Program (CAPS) and the University of Florida Institute of Food and Agricultural Sciences (IFAS). The project is multidisciplinary in nature and maximizes the relationship between the College of Agriculture and Food Sciences (CAFS), the Department of Biology, and the Environmental Sciences Institute at Florida A&M University (FAMU). This project strengthens existing partnerships and collaborative efforts between FAMU, the USDA-Agricultural Research Services, and the University of Florida. The project provides hands-on training opportunities to undergraduate students associated with the laboratory and field research activities. TARGET AUDIENCES: In the Southeastern United States, the redbay tree is an important forest species in the coastal plain. The economic importance of this tree is not limited to cabinet making, boatbuilding, and veneer work but in urban areas, redbay trees are often planted or are purposefully conserved during construction to beautify landscapes. Further, the redbay ambrosia beetle is a serious threat to several other rare trees in Florida, the avocado crop in south Florida, Mexico, Central America, and South America and to California bay laurels native to that state. The project thus benefits foresters, farmers, conservationists, and the community at large. PROJECT MODIFICATIONS: The project has been progressing successfully, but it is being terminated early because this project (Accession Number 221111) is a duplicative effort and all work and objectives that it would have addressed will now fall under project Accession Number 221112. Therefore, all future reporting will be done under 221112.

Impacts
The sampling regime was developed in cooperation with the Florida Cooperative Agricultural Pest Survey Program to regularly sample sites in the Apalachicola National Forest. To date, the redbay ambrosia beetle has not been found at the sampling sites (Camel Lake, Cotton Landing, and Wright Lake/Hickory Landing) in this large area of Panhandle Florida. However, more than 216 specimens of beetles belonging to the Xyleborina were collected from the Lindgren funnel traps and the specimens were then identified. Also, the pest species Corthylus punctatissimus Zimmermann was discovered for the first time in the Apalachicola National Forest. Among the Xyleborina collected, the dominant species (51.9%) was an invasive species Xyleborinus saxeseni (Ratzeburg). Subdominant species in the forest were, Xyleborus volvulus (Fabricius) (7.9%), X. ferrugineus (Fabricius) (8.8 % ), and X. affinis Eichhoff (9.3). %). Hypothenemus sp. (11.1 %) was also recorded in the Apalachicola National Forest. Our data indicated that those funnel traps using gel ethanol were significantly more attractive to ambrosia beetles than those using a mixture of Manuka and Phoebe oil. The project will continue to develop operational linkages and partnerships between FAMU and partner institutions (US Forest Service, Florida Department of Plant Industry Cooperative Agricultural Pest Survey Program). It will also help stakeholders understand the economic impact of this new invasive and destructive pest species, as well as the contribution of these natural resources to people and the community. The project will also generate the following impacts: (i) potential safeguards for all members of the Lauraceae family and several cultivated trees of economic importance including the state's $13 million-a-year avocado crop in south Florida, cultivated and wild avocados in Mexico, Central America, and South America, and the California bay (native to that state). It is anticipated that the project will provide a better knowledge of the (i) biology and dynamics of populations of the ambrosia beetle, (ii) identification of potential microbial control agents, (iii) development of an environmental friendly and sustainable management strategy for the redbay ambrosia beetle. The successful implementation of the findings of this project will lead to the development of an environmentally friendly and sustainable management strategy for the redbay ambrosia beetle.

Publications

• Latasha Tanner and Lambert Kanga. 2011. Evaluation of Monitoring Methods for the Redbay Ambrosia Beetle (Curculionidae: Scolytinae) in the Apalachicola National Forest. Entomological Society of America Southeastern Branch annual meeting, March 3-8, 2011. Little Rock, AR
• Latasha Tanner. 2011. Student News: Center for Biological Control Newsletter, Florida A&M University College of Agriculture and Food Sciences 10:8.