Source: UNIVERSITY OF FLORIDA submitted to NRP
CLASSICAL BIOLOGICAL CONTROL OF SELECTED INVASIVE EXOTIC PLANTS IN FLORIDA
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0198405
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2003
Project End Date
Sep 30, 2009
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611
Performing Department
INDIAN RIVER RESEARCH & EDUCATION CENTER, FT PIERCE
Non Technical Summary
Alien invasive plants are a major economic concern in agriculture, interfere with transportation and disrupt native ecosystems. This project will investigate and implement classical biological control options to reduce densities of alien invasive plants.
Animal Health Component
40%
Research Effort Categories
Basic
30%
Applied
40%
Developmental
30%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2022300108030%
2132300102020%
2152300113050%
Knowledge Area
215 - Biological Control of Pests Affecting Plants; 202 - Plant Genetic Resources; 213 - Weeds Affecting Plants;

Subject Of Investigation
2300 - Weeds;

Field Of Science
1130 - Entomology and acarology; 1080 - Genetics; 1020 - Physiology;
Goals / Objectives
Effective biological control of invasive alien plants through the introduction and establishment of host specific natural enemies. Initial plants to be addressed include Schinus terebinthifolius (Brazilian Peppertree), Dioscorea bulbifera (air potato) and Hymenachne amplexicaulis (West Indian marsh grass). Additional invasive weeds may be targeted during the course of this CRIS. a)Improve foreign exploration for natural enemies of Brazilian Peppertree by identifying the origin Florida populations through molecular characterization of its genetic diversity in Florida and South America. b)Determine the geographic distribution of Brazilian Peppertree, Schinus terebinthifolius, in Florida using remote sensing. c)Determine the geographic origin of air potato, Dioscorea bulbifera, in Florida as a first step towards initiating foreign exploration for biological control agents. d)Initiate collaborative activities with foreign scientists to identify host specific arthropod herbivores of air potato in its native home. e)Introduce candidate biological control agents of air potato into quarantine in Florida for non-target host testing. f)Conduct laboratory and field studies to describe the biology and host range of Ischnodemus variegatus, an exotic insect that feeds on the exotic invasive weed, Hymenachne amplexicaulis (West Indian Marsh Grass), in Florida. g)Evaluate the effect of Ischnodemus variegatus on growth, survival and reproduction of West Indian Marsh Grass. h)Evaluate the effect of Hymenachne amplexicaulis on plant and arthropod diversity in Florida fresh water marshes.
Project Methods
a) Samples of Brazilian Peppertree (BP) terminal buds will be collected throughout its geographic and ecological range in Florida. Samples will also be collected in South America by Dr. Jim Cuda and his collaborators. All samlpes will be geopositioned and mapped in GIS. Chloroplast DNA analyses will be conducted by Dr. Colin Hughes at the University of Miami who as on-going activities with BP genetics. b) Brazilian Peppertree samples, and samples of other plants which grow in the same habitats as BP, will be collected and spectrally analyzed by Dr. Jonathan Jordan at the Department of Agricultural and Biological Engineering. Large stands of BP will also be identified and geopositioned for spectral characterization. Landsat satellite images will be acquired and analyzed to delineate areas where BP is hypothesized to occur based on reflectance, and these areas will be ground-truthed to validate the analysis. Maps will be created of the BP distribution in southern and central Florida. c) The native home of air potato covers a vast geographic range in Africa and Asia, but the origin of Florida's air potato infestation is uncertain. To determine the origin, air potato will be collected throughout its range in Florida, characterized using chloroplast DNA or RAPDS, and compared to previously published information on genetic diversity of air potato in Asia and Africa. d) The results of (c) will suggest whether foreign exploration for candidate biological control agents of air potato should be focused in Africa or Asia. Once this is determined, collaboration will be initiated with institutes/scientists at appropriate locations in the native home. e) Working with collaborators at foreign institutes, candidate biological control agents of air potato will be identified. Initial host range testing will be conducted at the foreign institutes' laboratories, and later permission will be sought to import promising agents into Florida quarantine facilities for further non-target testing. f) In 2000, an insect was found feeding on, and causing considerable damage to the invasive grass, Hymenachne amplexicaulis, in Myakka River State Park near Sarasota. Taxonomists identified the insect as Ischnodemus variegatus, an exotic species from South America. A laboratory colony of I. variegatus will be initiated and studies will be conducted to determine its life history. Host range studies will be conducted with selected native and economically important grasses to determine whether the insect is a threat or beneficial in Florida. g) The impact of I. variegatus feeding on H. amplexicaulis will be evaluated in the laboratory and in field studies. Plants will be artificially infested with known numbers of insects and followed to determine the impact of feeding on plant growth, survival and reproduction. h) The effect of H. amplexicaulis on plant and arthropod community diversity in Florida fresh water marshes will be investigated using transect sampling methods. Diversity in ecologically similar infested and uninfested marshes will be compared.

Progress 10/01/03 to 09/30/09

Outputs
OUTPUTS: Surveys were conducted at 144 locations in ten lakes in Kenya, Uganda and Burundi to locate populations of Hydrilla verticillata. The plant was found at several locations in the littoral zone of Lake Tanganyika in Burundi, and in 4 lakes in Uganda (Bunyonyi, Mutanda, Bisina and Kyoga). A high diversity of chironomid midges was found associated with hydrilla at all locations sampled. Microscopic inspection of hydrilla stems revealed that chironomid larvae were commonly found on stems, but there were no signs of boring in stems or growing tips, or other evidence of herbivory. At all locations sampled, hydrilla plants typically had 30-80% of their growing tips missing, and leaves were often ragged or missing. Since we had not found insects associated with these damage symptoms, we tested the hypothesis that fish were feeding on hydrilla. Gills nets were used in Lake Bisina, Uganda to trap 36 species of fish. Dissection and inspection of gut contents revealed the presence of hydrilla leaves in 4 species of cichlids. An exclusion study is currently underway to measure the impact of fish herbivory on hydrilla. Analysis of chloroplast DNA revealed that Florida hydrilla was the same haplotype as plants from India and Africa, suggesting that African populations are the result of an introduction from India. China had very high genetic diversity, supporting an hypothesized Asian center of origin for hydrilla. Examination of 8 nuclear microsatellites revealed a surprising amount of genetic diversity in Florida, which we believe is the result of somatic mutations. Our data suggest that a single clone of hydrilla was introduced into Florida 50 years ago and has spread throughout Florida and the southern United States. Based on the genetic studies, which strongly suggest that hydrilla is not native to Africa, and the lack of insect herbivory, we believe that the prospects of finding host specific natural enemies of hydrilla in eastern/central Africa are low. The reasons that hydrilla does not reach high densities in east/central African lakes are unknown, but may be associated with fish herbivory, or to abiotic factors. Tropical soda apple: A biological control program against tropical soda apple (TSA) (Solanum viarum Dunal (Solanaceae)) released 176,643 Gratiana boliviana Spaeth (Coleoptera: Chrysomelidae) in Florida from 2003 to 2008. The spatial distribution of releases was clustered with more beetles released in south/central Florida than further north. A survey conducted in the fall of 2008 found G. bolviana present at > 70% of randomly selected locations between 26o and 29o latitude, but no beetles were found at sites further north. The presence of beetles and beetle damage were associated with smaller TSA plants and fewer fruit per plant. The absence of beetles in northern Florida may be due to the fewer number released in that area, but could also be influenced by land cover and climate. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Information gained from these studies on exotic plants and natural enemies will be used to explain establishment of biological control agents, or lack thereof, at various sites in Florida and neighboring states. Information gained will also be useful in selecting locations for future releases and to evaluate the impact of biological control agents on target weeds.

Publications

  • Diaz, R., W. Overholt, J. Cuda, P. Pratt, and A. Fox. 2009. Host specificity of Ischnodemus variegatus, an herbivore of West Indian marsh grass (Hymenachne amplexicaulis). BIOCONTROL 54: 307-321.
  • Manrique, V., J. Cuda, and W. Overholt. 2009. Effect of herbivory on growth and biomass allocation of Brazilian peppertree (Sapindales: Anacardiaceae) seedlings in the laboratory. BIOCONTROL SCIENCE AND TECHNOLOGY 19: 657-667.
  • Manrique, V., J. Cuda, W. Overholt, and S. Ewe. 2009. Influence of host-plant quality on the performance of Episimus unguiculus, a candidate biological control agent of Brazilian peppertree in Florida. BIOCONTROL 54: 475-484.
  • Manrique, V., J. Cuda, W. Overholt, and S. Ewe. 2009. Synergistic effect of insect herbivory and plant parasitism on the performance of the invasive tree Schinus terebinthifolius. ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA 132: 118-125.
  • Overholt, W., L. Markle, E. Rosskopf, V. Manrique, J. Albano, E. Cave, and S. Adkins. 2009. The interactions of tropical soda apple mosaic tobamovirus and Gratiana boliviana (Coleoptera: Chrysomelidae), an introduced biological control agent of tropical soda apple (Solanum viarum). BIOLOGICAL CONTROL 48: 294-300.
  • Overholt, W., R. Diaz, K. Hibbard, A. Roda, D. Amalin, A. Fox, S. Hight, J. Medal, P. Stansly, B. Carlisle, J. Walter, P. Hogue, L. Gary, L. Wiggins, C. Kirby, and S. Crawford. 2009. Releases, distribution and abundance of Gratiana boliviana (Coleoptera: Chrysomelidae), a biological control agent of tropical soda apple (Solanum viarum, Solanaceae) in Florida. FLORIDA ENTOMOLOGIST 92: 450-457.
  • Overholt, W. A., R. Copeland, D. Williams, B. Gidudu and B. Nzigidahera. 2009. Exploration for natural enemies of Hydrilla verticillata in Africa: A fishy story. 24th Annual Symposium of the Florida Exotic Pest Plant Council. May 26-29, 2009, Delray Beach, FL.
  • Diaz, R. and W. A. Overholt. 2009. Distribution and abundance of Gratiana boliviana (Coleoptera: Chrysomelidae), a biological control agent of tropical soda apple (Solanum viarum, Solanaceae) in Florida. 24th Annual Symposium of the Florida Exotic Pest Plant Council. May 26-29, 2009, Delray Beach, FL.
  • Diaz, R., W. A. Overholt, G. Wheeler, C. Aguirre and E. Rosskopf. 2009. Effects of light intensity on Tropical Soda Apple and the consequences for performance of its biological control agent, Gratiana boliviana (Chrysomelidae). Annual Meeting of the Florida Entomological Society July 26-29, 2009, Ft. Myers, FL
  • Cuda, J. P., V. Manrique, W. A. Overholt and S. Ewe. 2009. Synergistic effect of insect herbivory and plant parasitism on the performance of the invasive tree Schinus terebinthifolius (Anacardiaceae). 24th Annual Symposium of the Florida Exotic Pest Plant Council. May 26-29, 2009. Delray Beach, FL.
  • Diaz, R., W. A. Overholt, K. Gioeli, B. Sellers, and J. Medal. 2009. Biological control of tropical soda apple: a manual for the implementation of biological control as a tool for the management of tropical soda apple, Port St. Lucie, Florida.
  • Overholt, W. A., R. Diaz, K. Hibbard, A. Roda, A. Fox, S. Hight, J. Medal, P. Stansly, B. Carlisle, J. Walter, P. Hogue, L. Gary, L. Wiggins, Kirby, C., and S. Crawford. 2009. Distribution and abundance of Gratiana boliviana, a biological control agent of tropical soda apple, in Florida, Florida Cattleman and Livestock Journal, September, 2009.


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Tropical soda apple (Solanum viarum Dunal (Solanaceae) (TSA) is a South American invasive plant of rangelands, pastures and natural areas in Florida. A chrysomelid beetle from South America, Gratiana boliviana Spaeth, has been released at >300 locations in Florida for biological control of TSA since 2003. TSA is a host of several plant viruses, including the newly described Tropical soda apple mosaic virus (TSAMV). We investigated the influence of TSAMV infection of TSA plants on developmental time, leaf tissue consumption, longevity, fecundity and feeding preference of G. boliviana, and also tested transmission of the virus by the beetle. Developmental time was approximately 10% slower when beetles were fed on infected plants, and adults consumed only about 50% as much leaf tissue compared to uninfected plants. Longevity did not differ between females reared on infected and uninfected plants, but females fed on uninfected plants produced 71% more eggs than those fed on infected plants. Adult G. boliviana preferentially fed on uninfected plants when given a choice. There was no evidence of TSAMV transmission by G. boliviana. Temperature-dependent development and survival studies revealed that G. boliviana completed development at temperatures ≥ 16oC and ≤ 34oC. The number of degree-days required to complete one generation was 341 and the estimated lower developmental threshold was 13.4oC. Using nonlinear regression, the upper lethal threshold was estimated to be 34-35oC. Cold tolerance studies revealed that the lethal time for 90% of adults (LT90) was 12.6 days at 5oC and 8.7 days at 0oC. Based on the developmental and cold tolerance data, a map predicting the areas of establishment and number of generations per year was generated, which suggests that the northern extent of the G. boliviana range in the USA will be near 32-33o north latitude. Fewer generations per year in more northern areas of the southeastern USA may decrease the effectiveness of this biological control agent. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Information gained from these studies on exotic plants and natural enemies will be used to explain establishment of biological control agents, or lack thereof, at various sites in Florida and neighboring states. Information gained will also be useful in selecting locations for future releases and to evaluate the impact of biological control agents on target weeds.

Publications

  • Chinwada P, Schulthess F, Overholt W, Jowah P, Omwega C. 2008. Release and establishment of Cotesia flavipes for biological control of maize stemborers in Zimbabwe. Phytoparasitica 36(2): 160-167.
  • Diaz R, Samayoa AC, Overholt WA, Pitty, A. 2008. Solanum viarum Dunal (Solanaceae), primer reporte para Honduras. Ceiba 49(1): 133-134.
  • Diaz R, Overholt W, Cuda J, Pratt P, Fox A. 2008. Temperature-dependent development, survival, and potential distribution of Ischnodemus variegatus (Hemiptera : Blissidae), a herbivore of west Indian marsh grass. Annals of the Entomological Society of America 101(3): 604-612.
  • Diaz R, Overholt W, Samayoa A, Sosa F, Cordeau D, Medal J. 2008. Temperature-dependent development, cold tolerance, and potential distribution of Gratiana boliviana (Coleoptera : Chrysomelidae), a biological control agent of tropical soda apple, Solanum viarum (Solanaceae). Biocontrol Science and Technology 18(2):193-207.
  • Hailemichael Y, Schulthess F, Smith J, Overholt W, Chabi-Olaye A. 2008. Resource allocation and bionomics of indigenous and exotic Cotesia (Hymenoptera: Braconidae) species reared on Sesamia calamistis. Bulletin of Entomological Research 98(4): 405-415.
  • Jiang N, Zhou G, Overholt WA, Schulthess F. 2008. Host-parasitoid community model and its potential application in biological control of cereal stemborers in Kenya. Population Ecology 50(4): 405-416.
  • Diaz R, Overholt WA, Cuda JP, Pratt PD, Fox A. 2008. Biology, host specificity and potential impacts of West Indian marsh grass (Hymenachne amplexicaulis) in Florida. 23rd Annual Symposium of the Florida Exotic Pest Plant Council. 21-24 April, 2008. Jacksonville, FL.
  • Manrique V, Cuda JP, Overholt WA, Williams D, Wheeler G. 2008. Effect of host-plant genotype on the performance of Pseudophilothrips ichini, an approved biological control agent of Brazilian peppertree in Florida. 23rd Annual Symposium of the Florida Exotic Pest Plant Council. 21-24 April, 2008. Jacksonville, FL.
  • Mukherjee A, Gitzendanner M, Cuda JP, Overholt WA. 2008. Characterization of microsatellite DNA diversities of hygrophila (Hygrophila polysperma (Roxb.) T. Ander) in Florida. 23rd Annual Symposium of the Florida Exotic Pest Plant Council. 21-24 April, 2008. Jacksonville, FL.
  • Gioeli K, Langeland K, Cuda J, Overholt B and Medal JC. 2008. TAME invasives portal: A solution for your life. 23rd Annual Symposium of the Florida Exotic Pest Plant Council. 21-24 April, 2008. Jacksonville, FL.
  • Overholt W, Markle L, Adkins S, Rosskopf E. 2008. Studies on the interaction of a novel tobamovirus, TSAMV, and Gratiana boliviana. 23rd Annual Symposium of the Florida Exotic Pest Plant Council. 21-24 April, 2008. Jacksonville, FL.
  • Manrique V, Cuda JP, Overholt WA, Williams DA, Wheeler G. 2008. Effect of host-plant genotypes on the performance of three candidate biological control agents of Schinus terebinthifolius in Florida. Biological Control 47: 167-171.
  • Manrique V, Cuda J, Overholt W, Diaz R. 2008. Temperature-dependent development and potential distribution of Episimus utilis (Lepidoptera : Tortricidae), a candidate biological control agent of Brazilian peppertree (Sapindales : Anacardiaceae) in Florida. Environmental Entomology 37(4): 862-870.
  • Overholt W, Diaz R, Markle L, Medal J. 2008. Gratiana boliviana (Coleoptera : Chrysomelidae) does not feed on Jamaican nightshade Solanum jamaicense (Solanaceae). Florida Entomologist 91(1):121-123.
  • Sellers BA, Diaz R, Overholt WA, Langeland KA, Gray CJ. 2008. Control of West Indian marsh grass with glyphosate and imazapyr. Journal of Aquatic Plant Management 46: 189-192.
  • Cuda JP, Gillmore JL, Garcete-Barrett B, Medal JC, Overholt WA. 2008. Apocnemidophorus pipitzi (Coleoptera: Curculionidae), a new candidate for biological control of Brazilian peppertree, Schinus terebinthifolius (Anacardiaceae): Preliminary results of its biology and host range. 23rd Annual Symposium of the Florida Exotic Pest Plant Council. 21-24 April, 2008. Jacksonville, FL.
  • Overholt W, Langeland K, Diaz R. 2008. Jamaician nightshade: A plant poorly adapted to Florida or an exotic on the verge of rapid expansion. 23rd Annual Symposium of the Florida Exotic Pest Plant Council. 21-24 April, 2008. Jacksonville, FL.


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: The leaf beetle Gratiana boliviana Spaeth (Coleoptera: Chrysomelidae) is a classical biological control agent of tropical soda apple, Solanum viarum Dunal (Solanaceae) that was introduced into the southeastern United States beginning in 2003. Laboratory life table studies revealed that G. boliviana had a net reproductive rate of 40, an intrinsic rate of increase of 0.5 and a population doubling time of about 9 days. Temperature dependent development and survival studies revealed that development was completed at temperatures > 16oC and ≤ 34oC. The number of degree days required to complete one generation was 355. Non-linear models estimated the upper lethal threshold at 34-35oC and the lower developmental threshold at about 15oC. The Ltime90 was about 13 days at 5oC and 10 days at 0oC. Based on the cold tolerance data, a map predicting the areas of establishment and number of generations per year was generated which suggests that the northern extent of the G. boliviana range in the USA will be near 32-33 degrees north latitude. Fewer generations per year in more northern areas of the southeastern USA may decrease the effectiveness of this biological control agent. PARTICIPANTS: William A. Overholt, Associate Professor, University of Florida, Fort Pierce, FL Rodrigo Diaz, PhD student, University of Florida, Fort Pierce, FL Veronica Manrique, PhD student, University of Florida, Fort Pierce, FL Larry Markle, Biological Scientist, University of Florida, Fort Pierce, FL Freddy Sosa, Zamorano Intern, University of Florida, Fort Pierce, FL Ana Samoyoa, University of Florida, Fort Pierce, FL James P. Cuda, Associate Professor, University of Florida, Gainesville, FL Julio Medal, Visiting Scientist, University of Florida, Gainesville, FL Jonathan Jordan, Assistant-In. University of Florida, Gainesville, FL Matthew Croxton, MSc Student, University of Florida, Gainesville, FL Ken Hibbard, Florida Department of Agriculture, Division of Plant Industries, Fort Pierce, FL Amy Roda, USDA/APHIS/PPQ, Miami, FL Dean A. Williams, Assistant Professor, Texas Christian University, Fort Worth, TX Robert C. Copeland, Senior Scientist, International Center of Insect Physiology and Ecology, Nairobi, Kenya. Eric Muchugu, GIS specialist, International Center of Insect Physiology and Ecology, Nairobi, Kenya Brandford Mochiah, Entomologist, Crops Research Institute, Kumasi, Ghana. Mike Owusu-Akyaw. Senior Entomologist, Crops Research Institute, Kumasi, Ghana Paul Pratt, Research Scientist, USDA/ARS Invasive Plants Research Laboratory, Fort Lauderdale, FL Gregory Wheeler, Research Scientist, USDA/ARS Invasive Plants Research Laboratory, Fort Lauderdale, FL Georg Goergen, Scientist, International Institute of Tropical Agriculture, Cotonou, Benin. Professional Development Internship program. Our laboratory has established an undergradate internship program with the Panamerican School for Agriculture in Honduras (Zamorano) and Earth University in Costa Rica. Students complete a three month internship in our laboratory, with involvement in all aspects of weed biological, prior to completion of their undergraduate degrees. Additionally, several Zamorano students with research interests have completed 6 month internships at our laboratory after completing their undergraduate degrees. TARGET AUDIENCES: Land managers: In 2007, the project has provided extension training opportunities to private and public land managers at short courses organized by the University of Florida and the Florida Aquatic Plant Management Society. Additionally, the laboratory hosted two half day extension programs on biological control of tropical soda apple to ranchers. General public: In 2007, the project was involved in several extension events to increase awareness of the threat of invasive plants to Florida ecosystems and biological control of invasive plants. Scientific community: Project staff have presented their work to the scientific community through the presentation of research results at several state, national and international scientific conferences held in 2007.

Impacts
Information gained from this study will be used to explain establishment or lack there of Gratiana boliviana at various sties in Florida and neighboring states, and to select locations for future releases.

Publications

  • Diaz, R., W. A. Overholt, J. P. Cuda, P. Pratt and A. Fox. 2008. Temperature-dependent development, survival and potential distribution of Ischnodemus variegatus (Hemiptera: Blissidae), an herbivore of West Indian marsh grass (Hymenachne amplexicaulis). Annals of the Entomological Society of America (accepted).
  • Overholt, W. A., R. Diaz and J. Medal. Biological control of tropical soda apple in Florida: reuniting a South American plant with its natural enemy. Symposium of the International Organization of Biological Control, Merida, Mexico November 11-15, 2007.
  • Overholt, W. A., R. C. Copeland, D. Williams and J. P. Cuda. Exploration for Natural Enemies of Hydrilla in Africa - it ain't always easy..... Florida DEP and UF/IFAS Research Review for Invasive Plants in Florida, Ocala, Florida. 22-23 March 2007.
  • Overholt, W. A., M. Croxton, M. Andreu, D.Williams, B. Mochiah, M. Owuso-Akyaw and G. Goergen. Biological control of Dioscorea bulbifera: genetic characterization of Florida's population and foreign exploration for natural enemies in Africa. Florida DEP and UF/IFAS Research Review for Invasive Plants in Florida, Ocala, Florida. 22-23 March 2007.
  • Diaz, R., W. A. Overholt, J. P. Cuda, P. Pratt and A. Fox. Biology and host specificity of Ischnodemus variegatus (Blissidae), a potential biological control agent of Hymenachne amplexicaulis (Poaceae). Symposium of the International Organization of Biological Control, Merida, Mexico November 11-15, 2007.
  • Williams, D. A., J. P. Cuda and W. A. Overholt. Out of Florida: does Florida export invasive with high genetic diversity? Annual Symposium of the Florida Exotic Pest Plant Council. Cocoa Beach, FL April 30-May 3, 2007.
  • Diaz, R., W. A. Overholt and J. P. Cuda. Temperature-dependent development, survival and potential distribution of Ischnodemus variegatus (Hemiptera: Blissidae), an herbivore of West Indian marsh grass (Hymenachne amplexicaulis). Symposium of the International Organization of Biological Control, Merida, Mexico November 11-15, 2007.
  • Jordan, J. D., W. A. Overholt and J. P. Cuda. Baseline map and spectral library of pre-biocontrol of Schinus terebinthifolius Raddi in Florida. Symposium of the International Organization of Biological Control, Merida, Mexico November 11-15, 2007.
  • Manrique, V., J. P. Cuda, W. A. Overholt and D. Williams. Performance of two candidate biological control agents (Episiums utilis and Pseudophilothrips inchini) on four Brazilian peppertree genotypes found in Florida. Symposium of the International Organization of Biological Control, Merida, Mexico November 11-15, 2007.
  • Overholt, W. A., L. T. Markle, M. Garcia and S. M. L. Ewe. Allelopathic interactions between wax myrtle (Myrica cerifera) and Brazilian peppertree (Schinus terebinthifolius). Symposium of the International Organization of Biological Control, Merida, Mexico November 11-15, 2007.
  • Williams, D. A., S. Brown, J. P. Cuda, G. S. Wheeler, P. Madeira, B. Chapman and W. A. Overholt. Genetic relationships among Florida, African and Asian populations of Hydrilla verticillata. Symposium of the International Organization of Biological Control, Merida, Mexico November 11-15, 2007.
  • Medal, J. C., D. Gandolfo, W. Overholt, P. Stansly, A Roda, L. Osborne, K. Hibbard, R. Gaskalla, E. Burns, J. Chong, B. Sellers, S. Hight, and J. P. Cuda. 2007. Biology of Gratiana boliviana, the First Biocontrol Agent Released to Control Tropical Soda Apple in the USA. EDIS document ENY 828.
  • Diaz, R., W. A. Overholt and J. P. Cuda. Host specificity of a grass herbivore. XIIth International Symposium on Biological Control of Weeds, Montpellier, France. 22-27 April 2007.
  • Diaz, R., W. A. Overholt and J. P. Cuda. Temperature-dependent development, survival and potential distribution of Ischnodemus variegatus (Hemiptera: Blissidae), an herbivore of West Indian marsh grass (Hymenachne amplexicaulis). 7th Annual CALS Graduate Research symposium, University of Florida, Gainesville. 21 March 2007.
  • Diaz, R., W. A. Overholt and J. P. Cuda. Temperature-dependent development, survival and potential distribution of Ischnodemus variegatus (Hemiptera: Blissidae), an herbivore of West Indian marsh grass. 90th Annual Florida Entomological Society, Sarasota, Florida. 15-18 July 2007
  • Diaz, R., W. A. Overholt and J. P. Cuda. Biology and host specificity of Ischnodemus variegatus, an herbivore of West Indian marsh grass. Florida DEP and UF/IFAS Research Review for Invasive Plants in Florida, Ocala, Florida. 22-23 March 2007.
  • Manrique, V., J. P. Cuda, W. A. Overholt, and D. A. Williams. Evaluating the Performance of Episimus utilis (Lepidoptera: Tortricidae) on the Invasive Brazilian Peppertree in Florida. XIIth International Symposium on Biological Control of Weeds, Montpellier, France. 22-27 April 2007.
  • Manrique, V., J. P. Cuda, W. A. Overholt and D. Williams. Evaluating the survival of two candidate biological control agents (Episimus utilis and Pseudophilothrips ichini) on Brazilian peppertree genotypes. 90th Annual Florida Entomological Society, Sarasota, Florida. 15-18 July 2007
  • Manrique, V., J. P. Cuda and W. A. Overholt. Temperature-dependent development of the biocontrol agent Episimus utilis (Tortricidae), and its potential distribution in Florida. Annual Meeting of the Entomological Society of America. San Diego, CA. Dec 9-12, 2007.
  • Mohamed, S. A., W. A. Overholt, S. A. Lux, R. A. Wharton and E. Ml Eltoum. 2007. Acceptability and suitability of six fruit fly species (Diptera: Tephritidae) for Kenyan strains of Psytallia concolor (Hymenoptera: Braconidae). Biocontrol Science and Technology 17: 247-259.
  • Williams, D. A, E. Muchugu, W. A. Overholt and J. P. Cuda. 2007. Colonization patterns of the invasvive Brazilian peppertree, Schinus terebinthifolius, in Florida. Heredity 98: 284-293.
  • Gitau, C. W., A. J. Ngi-Song, S. A. Otieno and W. A. Overholt. 2007. Host preference of Xanthopimpla stemmator (Hymenoptera: Ichneumonidae) an its reproductive performance on selected African lepidopteran stem borers. Biocontrol Science and Technology 17: 499-511.
  • Overholt, W. A., R. Diaz, L. Markle and J. Medal. 2008. Gratiana boliviana (Chrysomelidae) does not feed on Jamacian nightshade (Solanum jamaicense (Mill.) (Solanaceae). Florida Entomologist (in press).
  • Billah, M. K., S. W. Kimani-Njogu, R. A. Wharton, W. A. Overholt, D. D. Wilson and M. A. Cobblah. 2007. Cross mating studies among five fruit fly parasitoid populations: potential biological control implications for tephritid pests. BioControl (published online first) http://www.springerlink.com/content/60lqj52r34656w09/fulltext.pdf


Progress 10/01/05 to 09/30/06

Outputs
Invasive species are believed to spread through a process of stratified dispersal consisting of short-distance diffusive dispersal around established foci and human mediated long-distance jumps. Brazilian peppertree(Schinus terebinthifolius), native to South America, was introduced as an ornamental in Miami on the east coast and Punta Gorda on the west coast of Florida, USA just over 100 years ago. A previous study indicated that these two introductions were from genetically differentiated source populations in the native range. In this study, we took advantage of these contrasting genetic signatures to study the spatial spread of Brazilian peppertree across its entire range in Florida. A combination of spatial genetic and geostatistical analyses using chloroplast and nuclear microsatellite markers revealed evidence for both long-distance jumps and diffusive dispersal. Chloroplast DNA haplotype distributions and extensive bands of intra-specific hybridization revealed extensive dispersal by both introduced populations across the state. In the northern most part of the range, there were patches of high ancestry for each introduction suggesting long-distance jump dispersal, probably by the movement of humans and migratory birds. The strong genetic signature of the original introductions around Miami and Punta Gorda, the presence of a general southeast to northwest genetic cline, and evidence for short-distance genetic spatial autocorrelation provided evidence of diffusive dispersal from an advancing front, probably by resident birds and small mammals. The evidence for extensive movement throughout the state suggests that Brazilian peppertree will be capable of rapidly recolonizing areas where it has been eradicated, making control efforts more difficult. Concerted eradication efforts over large areas or the successful release of biocontrol agents over a wide area will be needed to effectively suppress this species.

Impacts
Information gained from this study may prove useful for explaining the innvasiveness of Brazilian peppertree in Florida, and may also help in the design of a classical biological control approach.

Publications

  • Diaz, R., W. A. Overholt and J. P. Cuda. 2006. Damage of Ischnodemus variegates (Signoret) (Hemiptera: Blissidae) to the invasive grass Hymenachne amplexicaulis. 21st Annual Symposium of the Florida Exotic Pest Plant Council..April 24-26, Gainesville, FL.
  • Ewe, S. M. L., W. A. Overholt, L. G. Kirton, E. Lai, I. Ahmad and S. Ulaganathan. 2006. Foreign exploration for biological control agents of three invasive plant species from Asia. Wildland Weeds 9: 21.
  • Jiang, N., G. Zhou, W. A. Overholt, E. Muchugu and F. Schulthess. 2006. The temporal synchrony in the stemborer and parasitoid system of coast Kenya with climate effects. 2006. Annuals of the Entomological Society of France 42: xx-xx.
  • Manrique, V., J. P. Cuda and W. A. Overholt. 2006. Performance of two candidate biological control agents, Episimus utilis and Pseudophilothrips ichini on four Brazilian peppertree genotypes found in Florida. Annual meeting of the Entomological Society Meeting of America. Dec. 10-13, 2006. Indianapolis, IN.
  • Mohamed, S. A., W. A. Overholt, R. A. Wharton and S. A. Lux. 2006. The effect of temperature on developmental time and longevity of Psyttalia cosyrae (Hymenoptera: Braconidae). Biological Control Science and Technology 16: 717-726.
  • Overholt, W. A. 2006. Could Africa be a source of Hydrilla natural enemies? 21st Annual Symposium of the Florida Exotic Pest Plant Council..April 24-26, Gainesville, FL.
  • Omwega, C., Z. R. Khan and W. A. Overholt. 2006. ICIPE's quest for a sustainable solution to cereal stemborer problems in smallholder agriculture in Africa. Annual meeting of the Entomological Society Meeting of America. Dec. 10-13, 2006. Indianapolis, IN.
  • Williams, D. A., E. Muchugu, W. A. Overholt and J. P. Cuda. 2007. Colonization patterns of the invasive Brazilian peppertree, Schinus terebinthifolius, in Florida. Heredity (in press).
  • Kalyebi, A., W. A. Overholt, F. Schulthess, J. M. Mueke and S. Sithanantham. 2006. The effect of temperature and humidity on the bionomics of six African egg parasitoids (Hymenoptera: Trechogrammatidae). Bulletin of Entomological Research 96: 305-314.


Progress 10/01/04 to 09/30/05

Outputs
Schinus terebinthifolius, or Brazilian pepper, is an exotic invasive plant found throughout much of peninsular Florida. It rapidly colonizes disturbed areas, often forming dense monotypic stands, and displaces native vegetation. We examined a potential mechanism by which Brazilian pepper has become a major invader of Florida's ecosystems. In laboratory bioassays and greenhouse experiments, germination and biomass accumulation in two native Florida plant species, Bidens alba and Rivina humilis, were negatively affected by irrigation with aqueous extracts of Brazilian pepper leaves. Additionally, we examined potential allelopathic effects of a native tree, Morella cerifera, on Brazilian pepper, and found that the native negatively influences the performance of Brazilian pepper. This study illustrates a potential mechanism through which one plant may gain a competitive advantage over another, and suggests a possible tactic for management of Brazilian pepper using M. cerifera.

Impacts
Information gained from this study will be useful for explaining the innvasiveness of Brazilian peppertree in Florida, and may help to design appropriate integrated management approaches.

Publications

  • Midega C.A.O., C. K. P. O. Ogol and W. A. Overholt. 2005. Life tables, key factor analysis and density relations of natural populations of the spotted maize stemborer, Chilo partellus (Lepidoptera: Crambidae), under different cropping systems at the Kenyan coast.International Journal of Tropical Insect Science 25: 86-95.
  • Mohamed, H. M., Z.R. Khan, W.A. Overholt and D.K. Elizabeth. 2004. Behavior and biology of Chilo partellus (Lepidoptera:Pyralidae) on maize and wild gramineous plants. International Journal of Tropical Insect Science 24: 287-297.
  • Morgan, E. C. and W. A. Overholt. 2005. Potential allelopathic effects of Brazilian pepper (Schinus terebinthifolius Raddi Anacardiaceae) aqueous extract on germination and growth of selected Florida native plants. Journal of the Torrey Botanical Society. 132: 11-15.
  • Morgan, E. C. and W. A. Overholt. 2005. New Records of Exotic Invasive Species in St Lucie County, Florida. Castanea 70: 59-62.
  • Ngumbi, E., A. J. Ngi-song, L. Wadhams, J. Pickett, W. A. Overholt, R. Torto and B. Torto. 2005. Responses of the stem borer larval endoparasitioid Cotesia flavipes (Hymenoptera: Braconidae) to plant derived synomones: laboratory and field cage experiments. Biocontrol Science and Technology 15: 271-279.
  • Niyibigera, E. I., W. A. Overholt and R. Stouthamer. 2004. Cotesia flavipes Cameron and Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) do not exhibit Complementary Sex Determination: Evidence from field populations. Applied Entomology and Zoology 39: 705-717.
  • Niyibigera, E. I., W. A. Overholt and R. Stouthamer. 2004. Cotesia flavipes Cameron (Hymenoptera: Braconidae) does not exhibit Complementary Sex Determination (ii) Evidence from laboratory experiments. Applied Entomology and Zoology 39: 717-726.
  • Williams, D. A., W. A. Overholt, J. P. Cuda and C. R. Hughes. 2005. Chloroplast and microsatellite DNA diversities reveal the introduction history of Brazilian peppertree (Schinus terebinthifolius) in Florida. Molecular Ecology 14: 3643-3650.
  • Kanya, J. I., A. J. Ngi-Song, M. F. Setamou, W. A. Overholt, J. Ochora and E. O. Osir. 2004. Diversity of alternative hosts of maize stemborers in Trans-Nzoia district of Kenya. Environmental Biosafety Research 3: 159-168
  • Midega, C. A. O., C. K. P. O. Ogol and W. A. Overholt. 2005. Effect of Agroecosystem diversification on natural enemies of maize stemborers in coastal Kenya. International Journal of Tropical Insect Science 24: 280-286.
  • Billah, M. K., S. Kimani-Njogu, W. A. Overholt, R. A. Wharton, D. D. Wilson and M. A. Cobblah. 2005. The effect of host larvae on three Psyttalia species (Hymenoptera: Braconidae): parasitoids of fruit-infesting flies (Diptera: Tephritidae). International Journal of Tropical Insect Science 25: 1-8.
  • Cuda, J.P., J.C. Medal, W.A. Overholt, and J.H. Pedrosa-Macedo. 2005. Classical biological control of Brazilian peppertree, Schinus terebinthifolius (Anacardiaceae), in Florida: recent developments. Annual Meeting of the Southeastern Branch of the Entomological Society Meeting. March 7-9, 2005. Tunica, Mississippi.
  • Diaz, R., W.A Overholt, and J. Cuda. Impact Of Ischnodemus Variegatus (Hemiptera: Blissidae) on the invasive grass Hymenachne Amplexicaulis. 2005. Annual Meeting of the Southeastern Branch of the Entomological Society Meeting. March 7-9, 2005. Tunica, Mississippi.
  • Gitau, C. W., A. J. Ngi-Song, W. A. Overholt and S. A. Otieno. 2005. Acceptance and suitability of four gramineous stem borers (Lepidoptera: Crambidae, Noctuidae, Pyralidae) for the development of the pupal parasitoid Xanthopimpla stemmator (Hymenoptera: Ichneumonidae). Biocontrol Science and Technology 15: 585-600.
  • Gohole, L. S., W. A. Overholt, Z. R. Khan and L. E. M. Vet. 2005. Close-range host searching behavior of the stemborer parasitoids Cotesia sesamiae and Dentichasmias busseolae: influence of a non-host plant Melinis minutiflora. Journal of Insect Behavior 18: 149-169.
  • Kalyebi, A., S. Sithanantham, W.A. Overholt, S.A. Hassan, and J.M. Mueke. 2005.Parasitism, longevity and progeny production of six indigenous Kenyan trichogrammatid egg parasitoids (Hymenoptera: Trichogrammatidae) at different temperature and relative humidity regimes. Biocontrol Science and Technology 15: 255-270.


Progress 10/01/03 to 09/30/04

Outputs
The genetic structure of Brazilian peppertree in Florida was characterized using chloroplast and microsatellite DNA. Chloroplast DNA is maternally inherited and highly conserved, and therefore useful for identifying the origin of populations, whereas nuclear microsatellite data recombines during sexual reproduction. Analysis of chloroplast DNA has revealed the occurrence of two haplotypes of Brazilian peppertree in Florida, which have been arbitrarily designated at types A and B. The origin of the dominant Florida haplotype (A) has been found in southeastern Brazil, but a source population of the B haplotype has not been located. Microsatellite data also shows that two nuclear DNA types occur in Florida, one predominantly found in the southeast part of the state, and the other in the western side of the state. Hybrids of these two also exist. Together, these two sets of data strongly suggest the introduction of two genetic types Brazilian peppertree into Florida.

Impacts
Improved understanding of the genetic diversity of Brazilian pepper will be useful for identifying the South American source of the Florida population. Genotypes in South America that are similar to the invasive population in Florida should provide the best source of highly host specific insect herbivores. Additionally, knowledge of the genetic structure of Brazilian peppertree in Florida may help to explain its invasiveness. Hybridization between the two types may have led to novel traits that allowed the tree to rapidly adapt a variety of Florida habitats.

Publications

  • Diaz, R., W. A. Overholt, D. Cordeau and E. C. Morgan. 2004. Biology of Ischnodemus variegatus (Signoret) (Blissidae): a potential biological control agent of Hymenachne amplexicaulis. Joint conference of the Southeast Exotic Pest Plant Council and the Florida Exotic Pest Plant Council. Pensacola, Florida. p. 25.
  • Diaz, R., W. A. Overholt and J. P. Cuda. 2004. Exotics in the wetlands: West Indian marsh grass (Hymenachne amplexicaulis). EDIS publication ENY-693. 5 pp.
  • Ewe, S. M. L., W. A. Overholt, E. C. Morgan, R. Diaz and O. E. Moeri. 2004. A potential biological control agent of West Indian marsh grass (Hymenachne amplexicaulis) (Poaceae): documenting the impacts of Ischnodemus variegatus (Hemiptera: Blissidae) on the photosynthesis and growth of the invasive exotic grass. Joint conference of the Southeast Exotic Pest Plant Council and the Florida Exotic Pest Plant Council. Pensacola, Florida. p. 26.
  • Getu, E., W. A. Overholt and E. Kairu 2004. Comparative studies on the influence of relative humidity and temperature on life table parameters of two populations of Cotesia flavipes (Hymenoptera: Braconidae). Biocontrol Science and Technology 14: 595-605.
  • Huang, K. L., J. D. Jordan, W. A. Overholt and J. P. Cuda. 2004. GIS for baseline mapping of Brazilian peppertree (Schinus terebinthifolius Raddi) from multi-temporal remote sensing and field data. Joint conference of the Southeast Exotic Pest Plant Council and the Florida Exotic Pest Plant Council. Pensacola, Florida. p. 27-28.
  • Hughes, C., W. A. Overholt and C. Wallace. 2004. African origin of air potato. Joint conference of the Southeast Exotic Pest Plant Council and the Florida Exotic Pest Plant Council. April 28-30, 2004. Pensacola, Florida. p. 12-13.
  • Kalyebi, A., W.A. Overholt, S. Sithanantham, J.M. Mueke, S.A. Hassan and F. Schulthess. 2004. Functional response of six indigenous trichogrammatid egg parasitoids (Hymenoptera: Trichogrammatidae) in Kenya: Influence of temperature and relative humidity. Biocontrol Science and Technology 32: 164-171.
  • Medal, J., D. Gandolfo, J. Cuda, H. Pedrosa, E. Bredow, S. Hight, P. Stansly and B. Overholt. Biological control of tropical soda apple in Florida: one beetle released, four more coming. Joint conference of the Southeast Exotic Pest Plant Council and the Florida Exotic Pest Plant Council. April 28-30, 2004. Pensacola, Florida. p. 16-17.
  • Overholt, W. A., S. M. L. Ewe, R. Diaz, E. C. Morgan and O. E. Moeri. 2004. Feeding effects of Ischnodemus variegatus (Hemiptera: Blissidae) on photosynthesis and growth of Hymenachne amplexicaulis (Poaceae). Florida Entomologist 87: 312-316.
  • Overholt, W. A., R. D. Cave, P. D. Pratt, P. C. Lake and J. C. Scoles. 2004. Biological control containment facilities in Florida. EDIS publication ENY-710. 4 pp.
  • Overholt, W. A. and P. Pratt. 2004. Dispersal of Oxyops vitiosa: a biological control agent of Melaleuca in Florida. EDIS publication ENY-701. 3 pp.
  • Overholt, B. and C. Hughes. 2004. Origin of air potato disentangled. Biocontrol News and Information 25: 4-5.
  • Moeri, O. E., J. P. Cuda, W. A. Overholt, S. Bloem and J. E. Carpenter. 2004. Application of F1 sterility (F1SIT) for field host range testing of the South American leafrolling tortricid Episimus utilis, a candidate for classical biological control of Brazilian pepper in Florida. Annual Meeting of the Entomological Society of America. November 14-17, 2004. Salt Lake City, Utah.
  • Mohamed, S. A., W. A. Overholt, S. A. Lux and R. A. Wharton. 2004. Tritropic interactions of two Psyttalia spp. (Braconidae), six fruit flies (Tephritidae) and four fruits. 5Th Meeting of the Working Group on Fruit Flies of the Western Hemisphere. Fort Lauderdale, Florida. p. 94.
  • Morgan, E. C. and W. A. Overholt. 2004. Inhibitory effects upon germination and growth of selected native plants by Schinus terebinthifolius Raddi aqueous extracts. Joint conference of the Southeast Exotic Pest Plant Council and the Florida Exotic Pest Plant Council. Pensacola, Florida. p. 29.
  • Morgan, E. C., W. A. Overholt and K. A. Langeland. 2004. Wildland Weeds: Arrowhead Vine, Syngonium polyphyllum. EDIS publication ENY-715.
  • Morgan, E.C. and W. A. Overholt. 2004. Wildland Weeds: Paper Mulberry, Broussonettia papyrifera. EDIS publication ENY-702. 2 pp.
  • Overholt, W. A., D. W. Williams, C. R. Hughes and J. P. Cuda. 2004. Genetic diversity of Brazilian peppertree and implications for biological control. Annual Meeting of the Entomological Society of America. November 14-17, 2004. Salt Lake City, Utah.
  • Overholt, W. A. 2004. Origin of the Florida population of air potato and initial foreign exploration for biological control agents. Annual Meeting of the Florida Entomological Society. Fort Lauderdale, Florida.
  • Cardwell, K., D. E. Conlong, R. Goebel, Z. R. Khan, R. Kfir, W. A. Overholt, F. Schulthess and M. Setamou. 2004. Gramineous stemborers in Africa. pp. 997-990. In J. L. Capinera (ed.), Encyclopedia of Entomology. Kluwer Academic, Dordrecht, The Netherlands.
  • Chinwada, P., W. A. Overholt, C. O. Omwega and J. M. Mueke. 2004. Biology of Sturmiopsis parasitica (Diptera: Tachinidae) and suitability of three cereal stem borers (Lepidoptera: Crambidae, Noctuidae) for its development. Annals of the Entomological Society of America 97: 153-160.
  • Cuda, J. P., W. A. Overholt, K. T. Gioeli, C. R. Hughes and D. A. Williams. 2004. Characterization of the variability in the invasive Brazilian peppertree, Schinus terebinthifolius (Anacardiaceae): a genetic approach. Annual Meeting of the Weed Science Society of America. Kansas City, Missouri. p. 20.
  • Diaz, R., W. A. Overholt and D. Cordeau. 2004. Impact of Ischnodemus variegatus (Heteroptera: Blissidae) on the invasive grass Hymenachne amplexicaulis. Annual Meeting of the Entomological Society of America. November 14-17, 2004. Salt Lake City, Utah.