Progress 03/01/12 to 08/31/16

Outputs
Target Audience:The information obtained during this reporting period was primarliy disseminated to various research scientists who work in the areas of population genetics, invasive species and biological control. The information was disseminated through a research publication as well as presentation at various scientific meetings including the Greater Everglades Ecosystem Restoration Conference in Coral Springs, FL and the Florida Fish and Wildlife Conservation Commission Biannual Research Review meeting in Orlando, FL. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project trained one post-doctoral scholar who was promoted to Research Scientist during her tenure on the project. The Research Scientist was sent to 6 national scientific meetings over the course of the 4 year project where she either presented a poster and a talk on this research. How have the results been disseminated to communities of interest?The results have been disseminated through peer-reviewed journal publications (3), presentation at scientific conferences (8), invited presentations at Universities and Research Centers (6) and presentations to Parks and Wildlife departments (3). What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Nearly 1400 Imperata samples were collected from across the southeastern USA as well as Asia (India, Indonesia, Japan, Nepal, The Philippines, Papua New Guinea, Thailand and Vietnam), Africa (Benin, Cameroon, Congo, Democratic Republic of Congo, Ghana, Kenya, Liberia, Mozambique, Nigeria, Rwanda, South Africa, Tanzania, Togo, Uganda, Zambia, Zimbabwe), Australia, Brazil and Honduras. We used a cost-effective genotyping-by-sequencing (GBS) approach to identify the reproductive system, genetic diversity and geographic origins of invasions in the south-eastern United States. From the analysis of the SNPs identified in Imperata collected from known populations across the southeastern US 4 clonal lineages of Imperata cylindrica and 1 lineage of Imperata brasiliensis were resolved allowing us to conclude that there had been a minimum of four introductions of Imperata into the US. Our data also indicated that the founding of populations was primarily due to anthropogenic activities such as right-of-way maintenance via mowing and timber removal and transport due to the high genetic similarity of accessions in discontiguous populations.The conclusion that this species reproduces asexually and increases its invaded range primarily via rhizomatous spread and anthropogenic movement of rhizomatous propagules indicates that additional, accidental founding of new populations can be prevented with careful sanitation of propagule-vectoring equipment. Analysis of the global Imperata subset was completed in the final year of the project. A subset of 134 taxa and 2950 markers were included in this analysis to remove redundancy among the collected materials. An Asian/Indian Group which includes clonal lineages 1 and 2 from the US emerged as did an African group. Imperata brasiliensis remained as an isolated group as did Japanese Blood Grass (JBG). Upon analysis of the accessions collected from Africa, we found examples of accessions of an Asian-related population that was collected near the major port in Kenya which serves as a hub for Africa-Asia trade. This was the only example that would suggest recent establishment of a colony due to anthropogenic activities, athough we would caution that our collection was not inclusive of the entirety of all extant Imperata populations. Based on the complete data set obtained, it would be highly spectulative at this point to conclude where the true native range/Vavilov center of origin residdes, however, the results clearly point to regions best suited for biocontrol exploration. An intensive survey of the insect suite feeding on cogongrass, Imperata cylindrica, was conducted in its native range in both Asia and Africa. In Asia, field collection of insects was conducted in the Philippines (July 2013, March 2015), Japan (July 2013), and China (October 2015). In Africa, Kenya and Uganda were surveyed in May 2014. Insects were collected directly from cogongass by hand collection from roots, stems, leaves and seed heads. All insects including common generalist herbivores were collected, but the focus was on taxa that were known to be specialists such as Lepidopteran and Dipteran stem borers. Insects were identified using both classical taxonomy and molecular characterization. Insects that could not be readily identified with classical taxonomy were sent for DNA extraction and sequencing of the CO1 gene. Sequence data was blasted on Genbank to determine their closest match. Information from classical taxonomy and molecular characterization was used to survey published literature on biology and likely host range of the cogongrass insects. The results of the collection trips are summarized below. Asia 2013 - More than 100 locations were sampled for both plant DNA and insect herbivore diversity. In many areas, cogongrass formed large stands, especially where the landscape had been disturbed for agricultural uses. Insects were field identified to family and then sequenced to look for best matches on GenBank. More than 30 putative species were identified including root aphids, armored scales, soft scales, stem-boring flies and moths, root-feeding beetles and numerous leaf and stem feeding plant bugs. A stem-boring moth, Acrapex azumai Sugi (Lepidoptera: Noctuidae) was collected in Japan that shows promise as a specialist insect that could be a candidate biological control agent for cogongrass in the USA. Africa 2014 - More than 50 locations were surveyed from the lowlands of the Rift Valley in Kenya, wetlands around Lake Victoria to the highlands below the Rwenzori Mountains in Uganda in May 2014. This is an area of high biological diversity. More than 60 species of herbivore insects were collected from cogongrass in East Africa. In general, the I. cylindrica in East Africa is much larger in stature than populations in the southeastern USA and Asia. This phenotypical difference is confirmed by the molecular studies conducted by the group. In addition, specialist Acapex borers were collected live and returned to the Univ. of Florida. These borers did not find the invasive USA genotype of cogon suitable, most likely because they are adapted to larger diameter stems of the African I. cylindrica. In summary, the diversity of insects was higher in east Africa than anywhere we had previously sampled in Asia. Several groups of insects that are known to be specialists were collected including: stem boring Lepidoptera (moths), stem boring beetles, and highly diverse array of leafhoppers. From our experience, the diversity of insect taxa feeding on cogongrass shows that the plant has evolved in this region for a very long period of time. Philippines 2015 - The Philippines was revisited again in March 2015 to focus on collection and idenfitication specialist stem borers. Sixteen locations were surveyed on Luzon Island. Three Lepidoptera (moths) species were collected from cogongrass including Acrapex sp., and Chilo sp. China 2016 - China (Hong Kong) was surveyed in October of 2016. Six herbivore species were collected from 12 locations. In general, species diversity appeared similar to locations in Japan. The trip was cut short by rainfall and a broken arm. In summary, herbivore diversity was highest on cogongrass in Africa as compared to Asia. In Africa there were 135 unique genetic insect accessions as compared to 66 from Asia. Considering that more time was spent surveying in Asia, the putative origin of cogongrass, these numbers may indicate that insects have had more time to evolve cogongrass in East Africa as compared to Asia. We also observed a suite of specialist stemboring Lepidoptera in Africa on cogongrass and related grasses. The diversity of insect herbivore species in Africa appears to correlate with a high level of genetic diversity of cogongrass. The surveys conducted over the course of this project suggest the availability of specialized insect herbivores of cogongrass including several Acrapex species stemborers from East Africa as well as A. azumai from Japan. Attempts were made to rear several insect species, including Acrapex species from Japan and Africa, a Chio sp. from The Philippines and O. javanica from Indonesia by our entomologist collaborators, however, no insects were successfully colonized. This may relate to the genetic differences we discovered within the various cogongrass clonal lineages found within the US and globally or to the artificial diets that were also employed. Based on these observations, future efforts for rearing potential biological control agents might be more productive if the rearing was performed at laboratories in the native ranges of the candidate biological control agents where differences in host plant genotypes can be eliminated.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: W.A. Overholt, P. Hidayat, B. Le Ru, K. Takasu, J.A. Goolsby, A. Racelis, A.M. Burrell, D. Amalin, W. Agum, M. Njaku, B. Pallangyo, P.E. Klein and J.P. Cuda (2016) Potential biological control agents for management of cogongrass (Cyperales: Poaceae) in the southeastern USA. Florida Entomologist 99(4).
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Overholt, W. A., J. P. Cuda, J. A. Goolsby, A. M. Burrell, B. Le Ru, K. Takasu, P. E. Klein, A. Racelis and P. Hidayat. Prospects for biological control of cogongrass. Greater Everglades Ecosystem Restoration Conference. Coral Springs, FL. April 21-23, 2015.

Progress 03/01/14 to 02/28/15

Outputs
Target Audience: Information from this past year has been disseminated to Forestry commissions across several southeastern states and that information has been used for public education efforts. Information has also been disseminated to the scientific community through a publication as well as presentations at national meetings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? This project has provided opportunities for a research scientist to attend several meetings and present the research findings in both oral and written form. Dr. Burrell presented an invited talk at the Population and Conservation Genomics Workshop at the International Plant and Animal Genome Conference XXI in San Diego, CA and a poster at the Invasion Genetics: The Baker and Stebbins Legacy Symposium in Pacific Grove, CA. How have the results been disseminated to communities of interest? The results of this research has been disseminated through talks and posters at scientific meetings as well as through communication with forestry commissions throughout the southeastern US. The results have also been published in Molecular Ecology. What do you plan to do during the next reporting period to accomplish the goals? A comprehensive analysis of the molecular genetic data from both the US and all international samples collected to date will be analyzed to try to delimit the origins of the 4 clonal populations that have been identified within the southeastern US. Barcoding of insects collected from Uganda and Kenya will be completed and allow for characterization of specialist insects found feeding on cogongrass from this area of the world. A final trip to the Yunnan region of China will be initiated to identify specialists feeding on cogongrass for use as potential biological controls.

Impacts
What was accomplished under these goals? IMPACT: A genetic analysis and a comprehensive sampling of this species in the US and Asia indicated that US material reproduces asexually and that there are 4 types lineages present. We were able to match samples of 3 of the 4 types to samples collected abroad in Japan, China, Thailand and Vietnam. Since successful biological control of organisms that are primarily clonal is greater than those that undergo genetic changes to adapt to the areas they invade, the probability of identifying, evaluating and eventually deploying effective biological controls that only impact the types of Cogongrass in the US is dramatically increased. Geographical coordinates were collected for each sample that was sequenced. The geographical data indicates that the spread of this weed is due to anthropogenic activities. Our data shows patterns of high genetic similarity between accessions sampled in discontiguous geographical regions. This makes it possible to track the origin of material in newly reported populations, including new populations in North Carolina (where this species had never been observed before). This information provides additional incentive for land managers, forestry professionals and property owners to practice proper inspection and removal of any Cogongrass tissue from vehicle tires and equipment in order to prevent additional, accidental spread of this weed. From the genetic matching of samples of Cogongrass in the US to those collected abroad, our entomologist collaborators have traveled to regions with genetic matches overseas and surveyed for potential biological controls. These scientists have surveyed these areas and have identified insects feeding solely on Cogongrass and have initiated preliminary tests in quarantine laboratories to determine if these insects can survive outside of their native habitat and will feed on samples of US-collected Cogongrass in the laboratory and subsequently reproduce. Goals/Objectives Report Objective 1: Genetically identify the number of Cogongrass invasions to North America and the introduced ranges of each invasion. 1. Over 500 samples of Cogongrass were sampled from known populations in the US. This species is primarily limited to the southeastern states (AL, FL, GA, LA, MS, NC, SC, TX). The majority of the tissue sampling and GIS data associated with each accession was conducted by the state forestry commissions during their scheduled herbicide treatments of known populations. These samples were sequenced by high-throughput genotype by sequencing technology. A set of 2,320 informative single nucleotide (SNP) and insertion-deletion polymorphisms from Cogongrass were identified. Population genetic analysis using the software GENODIVE was used due to its flexibility to analyze both sexual and asexual populations, using an infinite alleles model necessary for SNP analysis. 2. Population genetic data analysis resolved 4 clonal lineages of I. cylindrica and 1 lineage of I. brasiliensis extant in the United States. 3. From this we concluded there had been a minimum of four introductions of Cogongrass into the United States. 4. The conclusion that this species reproduces asexually and increases its invaded range primarily via rhizomatous spread and anthropogenic movement of rhizomatous propagules indicates that additional, accidental founding of new populations can be prevented with careful sanitation of propagule-vectoring equipment. Objective 2: Identify probable source(s) and native range(s) of introduced populations in the United States 1. Samples were obtained by overseas collaborators from Asia (India, Indonesia, Japan, Nepal, The Philippines, Papua New Guinea, Thailand and Vietnam), Africa (Benin, Cameroon, Congo, Democratic Republic of Congo, Ghana, Kenya, Liberia, Mozambique, Nigeria, Rwanda, South Africa, Tanzania, Togo, Uganda, Zambia, Zimbabwe), Australia, Brazil and Honduras. These samples were sequenced and analyzed identically to the methodology in Objective 1. 2. From this analysis, we detect genetic matches of US accessions to those found in the Yunnan Province of China, the Shandong Province of China, Japan, Thailand and Vietnam, which were members of 3 of the 4 clonal lineages of I. cylindrica in the US. As a proof of concept, the I. brasiliensis clonal lineage was retained in samples from Brazil and Honduras. 3. The inclusion of these international samples in identical clonal lineages provide evidence that at least three of these lineages showed clonal reproduction prior to introduction to the United States. These results indicate Cogongrass has limited evolutionary potential to adapt to novel environments, and further suggest that upon arrival to its invaded range, this species did not require local adaptation through hybridization/introgression or selection of favorable alleles from a broad genetic base. Objective 3: Assess levels of genetic diversity within and among populations of US Cogongrass. 1. Genetic diversity within and among populations of US Cogongrass and I. brasiliensis was assessed using the software GENODIVE. 2. From these analyses, we observed insignificant levels of genetic diversity within the overwhelming majority of populations of Cogongrass as well as within the clonal lineages. Where genetic diversity was detected in populations, it was determined that these populations contained accessions from different clonal lineages. The detected diversity in those populations was not due to hybridization among the different clonal lineages. 3. The lack of genetic diversity within populations of Cogongrass indicates asexual reproduction. The lack of hybridization among members of different clonal lineages in populations composed of multiple clonal lineages further supports that this species' principal mode of colonization is asexual. 4. The conclusion that this species reproduces asexually and has not undergone adaptive genetic changes in its US invaded range is extremely encouraging for the possibility of successful biological control of Cogongrass in the United States. Objective 4: Integrate genotypic data with geographical data in order to produce a predictive model for future invasion as well as a guide for targeted biological control release. 1. GIS data was collected for all samples that were sequenced. 2. Integrating the genetic data with the geographical data produced a distribution map of genotypes in the US. 3. Preliminary data show that potential controls that have been collected are clonal lineage-specific in feeding tests and insect-rearing efforts. Objective 5: Survey the insect herbivores in the native range(s) of the invasive genotype(s) of Cogongrass 1. In the summer of 2014, an intensive survey of the insect suite feeding on Cogongrass was conducted in the Kenya and Uganda. More than 50 locations were sampled for both plant DNA and insect herbivore diversity. Habitats from the lowlands of the Rift Valley in Kenya, wetlands around Lake Victoria to the highlands below the Rwenzori Mountains were surveyed. This is an area of high biological diversity. They were accompanied by scientists from INRA and ICIPE that have worked for the last 10 years collecting and describing the stemborers of East African grasses. 2. More than 60 species of herbivore insects were collected from Cogongrass in East Africa. In general, the I. cylindrica in East Africa is much larger in stature than populations in the southeastern USA and Asia. This phenotypical difference is confirmed by the molecular studies conducted by the group. In addition, specialist Acapex borers were collected live and returned to the Univ. of Florida. 3. These borers did not find the invasive USA genotype of Cogongrass suitable, most likely because they are adapted to larger diameter stems of the African I. cylindrica. Objective 6: Determine the suitability of the insects as potential biological control agents based on their field host specificity. 1. Objective 6 will be addressed in Year 4 of funding.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Burrell, A.M., A.E. Pepper, G. Hodnett, J.A. Goolsby, W.A. Overholt, A.E. Racelis, R. Diaz and P.E. Klein (2015) Exploring Origins, Invasion History and Genetic Diversity of Imperata cylindrica (L) P. Beauv. (Cogongrass) in the United States using Genotyping by Sequencing. Mol. Ecol. doi:10.1111/mec.13167.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: A.M. Burrell, A.E. Pepper, G. Hodnett, J.A. Goolsby, W.A. Overholt, A.E. Racelis, R. Diaz and P.E. Klein (2015) Exploring Origins, Invasion History and Genetic Diversity of Imperata cylindrica (L.) P. Beauv. (Cogongrass) in the United States using Genotyping by Sequencing. Plant and Animal Genome XXII, W640.

Progress 03/01/13 to 02/28/14

Outputs
Target Audience: The information obained from our research is disseminated to various forestry commissions that deal with cogongrass invasions. These forestry commissions have used the research findings from this work to educate the public on the spread and invasiveness of this noxious weed. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Research Scientist, M. Burrell, has received training in genotyping-by-sequencing and analysis of next generation sequencing data. She has been given the opportunity to present her research findings at several national/international meetings and has also been invited to present her work to graduate students at Claremont Graduate University in Claremont, CA. How have the results been disseminated to communities of interest? Results from gentoypic analysis of cogongrass samples from the US has been disseminated to forestry commissions who are responsbile for controlling this invasive species. Additionallly the research results have been disseminated at national and international meetings to other research scientists. M. Burrell has also participated in a podcast for The Wilderness Center to discuss ecosystem change due to introduced native species. What do you plan to do during the next reporting period to accomplish the goals? During the coming year we will complete genotypic analysis of all international samples in order to match genotypes in the US to genotypes sampled internationally. This work will allow us to determine the most appropriate locations to survey for natural enemies for use as potential biological controls. J. Goolsby will lead a second expedition to international regions that show promise for identification of potential biological controls. A manuscript profiling the populations of Imperata spp. in the United States will be completed as will a second profiling US and international samples.

Impacts
What was accomplished under these goals? Incorporation of international genotypic data has pinpointed regions with significantly genetically similar genotypes extant in the US. To date, our data suggest that the predominant ecotype that occurs throughout the Southern states, including the panhandle of Florida and north to South Carolina and, most recently, North Carolina, is uniquely isolated to Japan. The ecotype found in the peninsular region of Florida shows strong correlations with accessions acquired from The Philippines and the Yunnan Province of China, in particular. Sequencing data of Imperata brasiliensis samples from Dade County, Florida and multiple regions in Brazil illustrate that this species is indeed genetically distinct from any of the I. cylindrica strains in the US. Where I. cylindrica is sympatric with I. brasiliensis, no evidence of hybridization between the two species has been observed. Our data suggest the horticultural Japanese Bloodgrass (which can shift to an invasive phenotype) and the vast majority of material thus collected from the African continent are more closely related to I. brasiliensis than I. cylindrica.

Publications

• Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: K. Takasu, Y. Yoshiyasu, A.M. Burrell, P. E. Klein, A. Racelis, J. A. Goolsby, and W. A. Overholt. 2014. Acrapex azumai Sugi (Lepidoptera: Noctuidae) as a possible biological control agent of the invasive weed Imperata cylindrica (L.) Beauv. (Poaceae) in the United States. Lepidopteran Science.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: M. Burrell, A. Pepper, J. Goolsby, W. Overholt and P. Klein. Genomics of Imperata cylindrica. Plant and Animal Genome Conference XXII, San Diego, CA. W838
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: P. Klein, M. Burrell, A. Pepper, and J. Goolsby. Genetic characterization of Imperata cylindrica using a genotyping by sequencing approach: identifying international regions for potential biological control exploration and development. Joint Meeting of the Weed Science Society of America and the Canadian Weed Science Society. Vancouver, B.C. 188
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: M. Burrell and P. Klein. Using genotyping by sequencing to genetically characterize global accessions of the noxious weed, Imperata cylindrical. Joint Meeting of the Weed Science Society of America and the Canadian Weed Science Society. Vancouver, B.C. 86
• Type: Other Status: Other Year Published: 2014 Citation: M. Burrell. Wild Ideas...The Podcast 242. Interview by The Wilderness Center (wildernesscenter.org). Air date: January 2, 2014.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: M. Burrell. Combating the global threat of invasive species using high-throughput, high resolution genomics: Imperata cylindrica (Cogongrass) as a case study. Annual National Conference of the Society for the Advancement of Chicanos/Hispanics and Native Americans in Science.

Progress 03/01/12 to 02/28/13

Outputs
OUTPUTS: In Year One of funding, the overall goal was to comprehensively sample and genotype populations of Cogongrass in the United States in order to determine the amount of genetic diversity as well as primary colonization mode of this highly invasive weed species. To obtain an inclusive collection of samples, we facilitated a partnership with the state forestry commissions of Cogongrass-infested states (AL, FL, GA, LA, MS, SC, and TX). State foresters collected plant tissue as well as GPS coordinates for each sample collected, prior to scheduled herbicide treatments. The Alabama and Mississippi Forestry Commissions assisted M. Burrell and P. Klein in April of 2012 when they visited two well-documented historical populations of Cogongrass which they sampled intensively. The foresters took M. Burrell and P. Klein to locations that have been consistently treated with herbicide for many years and show no significant reduction in population size. Over 500 Cogongrass samples were sequenced and analyzed by M. Burrell and P. Klein in Year One. Additionally, M. Burrell and P. Klein elected to have a whole genome library of Cogongrass sequenced for additional bioinformatic capability and to better characterize the genome of Cogongrass. Additional collaborations were formed with the University of Florida, The Nature Conservancy, The Florida Fish and Wildlife Conservation Commission, parks and recreation professionals, and citizen scientists, who have generously assisted the team in collection of Cogongrass on private and publically-managed properties. Toward the end of Year One, collaborations were formed with scientists in international regions suggested to be the origin of Cogongrass. To date, scientists in Japan, China, The Philippines, Indonesia, Congo, Australia and Tanzania have provided samples for sequencing in Year Two. Forthcoming samples will come from Kenya, South Africa, Uganda, Ethiopia, Nigeria, Ghana, Mozambique and Brazil. P. Klein attended the NIFA-AFRI Project Director meeting to report the results of Year One. M. Burrell attended the Ecological Genomics Conference in Kansas City, MO and Plant and Animal Genome in San Diego, CA to disseminate research findings. PARTICIPANTS: Patricia Klein (PD) conducted Cogongrass collection in Mississippi and Alabama in April of 2012. Additionally, PD Klein has performed all bioinformatic analyses of Cogongrass samples genotyped. Co-PD Millie Burrell conducted Cogongrass collection in Mississippi and Alabama in April of 2012 and has prepared more than 500 Cogongrass samples for digital genotyping on an Illumina sequencer. Co-PD Burrell has also worked with state forestry commissions on sample collection procedures and has participated in data analysis. Co-PD Alan Pepper has assisted with data interpretation. Partnerships with state forestry commissions in Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina and Texas have been established. Foresters from these states have collected Cogongrass tissue samples as well as GPS coordinates for each sample collected. Additional collaborations were formed with the University of Florida, The Nature Conservancy, The Florida Fish and Wildlife Conservation Commission, parks and recreation professionals, and citizen scientists, who have generously assisted the team in collection of Cogongrass on private and publically-managed properties. Co-PD Burrell was sent to two meetings during year one to present research results and to aid in her professional development. TARGET AUDIENCES: The information obtained from the genotypic analysis of Cogongrass samples collected across the southeastern US has been disseminated to the various forestry commissions that deal with Cogongrass invasions. The finding that one of the three ecotypes identified is the horticultural variety, Red Baron, indicating that this variety can revert to an invasive form has been used by the forestry commissions to educate the public regarding the invasiveness of this grass. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Sequence data suggests that US genotypes of Cogongrass are divided into three distinct ecotypes. The predominant ecotype occurs throughout the Southern states, including the panhandle of Florida and north to South Carolina. A distinctive ecotype is found in the peninsular region of Florida, where it is sympatric with Brazilian Satintail (Imperata brasiliensis). Samples of Brazilian Satintail are to be included in genetic analyses. The third ecotype is a horticultural cultivar (Red Baron) that has escaped cultivation and become invasive. The distribution of the horticultural cultivar is sporadic. Our genetic analysis revealed limited gene flow both within and between the populations. This data reinforces the suspicion that the primary method of reproduction of this species is clonal and through aggressive rhizomatous invasion.

Publications

• 1. Burrell, A.M. and Klein, P.E. 2013. Using population genomics to combat Imperata cylindrica (L.) Beauv (Cogongrass, Speargrass), a noxious weed of extensive global impact. International Plant and Animal Genome XXI, San Diego, CA, January, 2013.
• 2. Burrell, A.M. and Klein, P.E. 2012. Using genotyping by sequencing as a first step to develop biological controls for the noxious weed, Imperata cylindrica (L.) Beauv., a highly successful invader causing ecosystem-level destruction in the southeastern United States. 10th Annual Ecological Genomics Symposium, Kansas City, MO, October, 2012.