Progress 10/01/03 to 10/01/09
Outputs
OUTPUTS: Activities: Plant-parasitic nematodes cause serious damage to turfgrass and ornamentals. Postplant nematicides have been used for the management of phytoparasitic nematodes in turf for more than 20 years. These chemicals pose health and environmental risks requiring the development of alternative strategies such as biological control. Pasteuria bacteria and biorational compounds may have potential for postplant management of phytoparasitic nematodes in perennially managed turf ecosystems. Development of new strategies for postplant management of nematodes will be beneficial to sustained maintenance of turf and ornamentals in the landscape. We have continued working with Abamectin (AVID) and Emamectin Benzoate (Proclaim) formulations to assess their acute toxicity to the sting nematode (Belonolaimus longicaudatus). We examined the dose (PPM) of AVID 0.15 EC versus predicted probabilities for mortality of sting nematode (20 nematode adults per replicate X 4 reps) after 2 and 24 hours of exposure with LD50s at less than 100 PPM. We also examined the dose of PROCLAIM 5 SG versus predicted probabilities for mortality of sting nematode after 2 and 24 hours exposure and found that no tested dose was lethal to 50% of the population. We also evaluated AVID 0.15 EC and PROCLAIM 5 SG relative to a commercial standard organophosphate nematicide (Nemacur) in a potted FX-313 St. Augustinegrass pot study for 6 weeks to determine if they suppress sting nematodes and/or improve plant performance. The materials were applied three times (at the start and at 2 and 4 weeks) vs. Nemacur which was only applied at the start. Under the conditions of this experiment, none of the compounds or combinations significantly suppressed sting nematode populations relative to the Nemacur control at 6 weeks. We have also continued working on Pasteuria bacteria for biological control of nematodes. Dissemination of new information from this project has been accomplished mainly through publication in refereed publications, student theses, reports, and presentations at national or local meetings. Events: Giblin-Davis, R. M. 2009. Master Gardeners presentation. Introduction to Nematodes in the landscape. Broward County Extension, Fort Lauderdale, FL. March 3, 2009. Invited speaker. (30 participants). Giblin-Davis, R. M. 2009. University of Florida/IFAS Fort Lauderdale Turf Field Day. Turf Nematology Update in Florida. Fort Lauderdale, FL. March 26, 2009. Invited speaker. 6 X 15 min talks to groups of ca. 20 each. Giblin-Davis, R. M. 2009. Palm Management in the Florida Landscape. University of Florida/ IFAS extension. Palm Insects; Borers, Defoliators and Sap suckers. Fort Lauderdale, FL. February 5-6, 2009. Invited speaker. (40 participants). Giblin-Davis, R. M. 2009. Palm Management in the Florida Landscape. University of Florida/ IFAS extension. Palm Insects; Borers, Defoliators and Sap suckers. Fort Lauderdale, FL. October 27-28, 2009. Invited speaker. (40 participants). Giblin-Davis, R. M. 2009. Harrell's presentation. Introduction to Pasteuria for biological control of turf nematodes. PGA Conference Center, Palm Beach, FL. December 15, 2009. Invited speaker. (30 participants). PARTICIPANTS: PI: Robin M. Giblin-Davis, Professor, Fort Lauderdale Research and Education Center, Department of Entomology and Nematology, University of Florida; role: provided research expertise and director of nematode identification, nematode morphology and molecular systematics, biological control and bioassay methodology for screening biorational materials. Graduate students: Supervisory Committee member for Mr. Joey Orajay's doctoral project (2005-2009). Supervisory Committee member for Eric Luc, doctoral project (2006-2009). Supervisory Committee member for Wenjing Pang, doctoral project (2008-present). Collaborators: Barbara J. Center, FLREC, University of Florida, Maintains nematode cultures, conducts biorational bioassays, cultures Pasteuria, runs routine soil samples for nematodes, curates nematology collection, does morphometric analyses, helps with PCR amplifications and databasing. TARGET AUDIENCES: Landscape managers, golf course superintendents, sod producers, Master gardeners, concerned home owners, palm enthusiasts, city and county field managers, pest control operators. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Belonolaimus longicaudatus (sting nematode) is a serious problem on bermudagrass, a common warm-season turfgrass, in Florida. We described a new species of bacterium Candidatus Pasteuria usgae that is an obligate parasite of sting nematode. Field data demonstrated that this bacterium can cause significant reductions of sting nematode in the field and has great potential as a biological control agent. Pasteuria Bioscience in Alachua, Florida has commercially cultured C. P. usgae on artificial media and it is being released as a commercial product (Econem)in January 2010 by Harrell's fertilizer Corp. Ph.D. student, Mr. Eric Luc, has continued to complete greenhouse and field experiments with C. P. usgae to evaluate it as an inundative biopesticide. I serve as committee member on his Ph.D. committee with Dr. Billy Crow (Chair). Greenhouse and field trials were completed this year and Mr. Luc defended his thesis and has been awarded a Ph. D. Mr. Luc also presented a paper this year in the student paper competition at the Society of Nematology meeting in Vermont. (Luc, J. E., W. T. Crow, R. McSorley, J. B. Sartain, and R. M. Giblin-Davis. Effects of irrigation, thatch, and a wetting agent on Candidatus Pasteuria usgae endospore placement in turf. Society of Nematologists-Soil Ecology Society (SON/SES) Joint Annual meeting, Burlington, Vermont, July 12-15, 2009). A putative Pasteuria species, strain R-1, which parasitizes a bacterial feeding nematode, Bursilla sp. was discovered in bermudagrass (Cynodon sp.) field plots at the FLREC in Davie, FL. This strain of R-1 Pasteuria is maintained by continuously adding >500,000 Bursilla sp. every 2 weeks to a soil sample from the field where the isolate had been identified. It was distinguished from other described species of Pasteuria using ultrastructure of the mature endospores and comparisons of genes encoding 16S rRNA. This is the first report of sustained in vivo culture of an isolate of Pasteuria on a bacterivorus nematode. The description of this prokaryote was completed and a manuscript was submitted (Giblin-Davis, R. M., G. Nong, J. F. Preston, D. S. Williams, B. J. Center, J. A. Brito, and D. W. Dickson. 2010. Candidatus Pasteuria xxxxxi sp. nov., an obligate endoparasite of the bactivorous nematode, Bursilla sp. International Journal of Systematic and Evolutionary Microbiology). We plan to use it as a comparative genomic model with other Pasteuria species that attack plant-parasitic nematodes. I also served on the Ph. D. committee of Mr. Joey Orajay, who completed his dissertation this year on a project developing molecular approaches for more sensitive detection of a new species of Pasteuria sp. parasitizing ring nematodes in peanut and other crops such as turf.
Publications
- McGroary, P., W. T. Crow, R. McSorley, R. M. Giblin-Davis, and J. L. Cisar. 2009. Seasonal fluctuations of Belonolaimus longicaudatus in bermudagrass. Nematropica. 39:99-110.
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Activities: Plant-parasitic nematodes cause serious damage to turfgrass and ornamentals. Postplant nematicides have been used for the management of phytoparasitic nematodes in turf for more than 20 years. These chemicals pose health and environmental risks requiring the development of alternative strategies such as biological control. Pasteuria bacteria and biorational compounds may have potential for postplant management of phytoparasitic nematodes in perennially managed turf ecosystems. Development of new strategies for postplant management of nematodes will be beneficial to sustained maintenance of turf and ornamentals in the landscape. We have continued working on Pasteuria bacteria for biological control of nematodes. Accurate identification of nematodes and elucidating their phylogenetic relationships is critical to understanding their pathology. We have continued working on the molecular phylogeny and systematics (using mtCOI, SSU and LSU loci) of Bursaphelenchus and other species of plant-and fungal-feeding Aphelenchoidea to understand how this group may have evolved to parasitize plants. This includes members of the genera Aphelenchoides, Schistonchus, Ektaphelenchus, and others. This has resulted in several publications. Ficus (Moraceae) is a diverse plant genus with more than 700 species worldwide. The plant genus Ficus is an important commercial fruit plant, ornamental and potential weed in the United States. Two genera of nematodes, Schistonchus and Parasitodiplogaster, are exclusively known from associations within the sycones of Ficus and inside their fig wasp pollinators. Schistonchus is apparently codistributed with Ficus species around the world. Entomophilic females or other stages are carried in the hemocoel of the fig wasps (either as parasites or internal phoretics). Once inside the sycone the nematode becomes plant-parasitic and feeds mostly on floret epidermal cells causing hypertrophy and/or necrosis. An extensive biogeographical survey was conducted of nematodes associated with the edible fig, Ficus carica in seven different regions of Turkey. Figs (syconia) were collected, dissected and harvested for nematodes from 308 apparently wild or naturalized F. carica trees along roadsides and trails. Nematode specimens were examined morphologically and molecular analyses of sequences of the D2/D3 expansion segments of the large subunit (LSU) rDNA and partial mitochondrial DNA COI (mtCOI) were done. One hundred fifty of the 308 (49%) fig trees were positive for what was morphologically confirmed to be Schistonchus caprifici. No geographic patterns were observed for either locus suggesting that the sequences generated represent inherent intraspecific variation for S. caprifici and that anthropogenic activities related to the culture of the edible fig have allowed for mixing of any previously allopatric lineages. PARTICIPANTS: PI: Robin M. Giblin-Davis, Professor, Fort Lauderdale Research and Education Center, Department of Entomology and Nematology, University of Florida; role: provided research expertise and director of nematode identification, nematode morphology and molecular systematics. Partner Organizations: Dr. Natsumi Kanzaki; Forest Pathology Laboratory, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687 Japan; Helped with Bursaphelenchus and taxonomy and sequencing projects; Dr. Weimin Ye; Nematode Assay Section, North Carolina Department of Agriculture & Consumer Services, Raleigh, NC; Helped with Bursaphelenchus and taxonomy and sequencing projects; Dr. W. Kelley Thomas and Krys Morris; Hubbard Center for Genome Studies, University of New Hampshire, Durham, NH; Helped with molecular amplification and sequencing projects; Dr. Nevin Keskin and Canan Hazir, Department of Biology, Hacettepe University, Ankara, Turkey; Helped with nematode collections, taxonomy and processing; Dr. Selcuk Hazir and Baris Gulcu, Department of Biology, Adnan Menderes University, Aydin, Turkey; Directed students and helped with taxonomy and molecular studies of nematodes. Collaborators: Barbara J. Center, FLREC, University of Florida, Maintains nematode cultures, curates nematology collection, does morphometric analyses, helps with PCR amplifications and databasing. TARGET AUDIENCES: Giblin-Davis, R. M. 2008. University of Florida/IFAS Fort Lauderdale Turf Field Day. Turf Nematology Update in Florida. Fort Lauderdale, FL. April 3, 2008. Invited speaker. 6 X 15 min talks to groups of ca. 20 each. (audience: Turfgrass professionals and extension agents). Giblin-Davis, R. M. 2008. Palm Management in the Florida Landscape. University of Florida/ IFAS extension. Palm borers. Fort Lauderdale, FL. May 7-8, 2008. Invited speaker. (40 participants). (audience: Ornamental and landscape professionals, growers and extension agents). Giblin-Davis, R. M. 2008. Palm Management in the Florida Landscape. University of Florida/ IFAS extension. Palm Insects; Borers, Defoliators and Sap suckers. Fort Lauderdale, FL. October 28-29, 2008. Invited speaker. (41 participants). (audience: Ornamental and landscape professionals, growers and extension agents). Nematology 3002;5002 (Principles of Nematology; Graduate Survey of Nematology), FLREC and distance education; 15 X 3 hr lectures (36 students). (Spring 2008). Taught using examples from research with nematodes of turfgrasses and ornamentals. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We described a new species of bacterium Candidatus Pasteuria usgae that is an obligate parasite of sting nematode. Field data demonstrated that this nematode can cause significant reductions of sting nematode and has great potential as a biological control agent for sting nematode. Pasteuria Bioscience in Alachua, Florida has successfully cultured Candidatus Pasteuria usgae on artificial media on a commercial scale. This has allowed a PhD student, Mr. Eric Luc, to make progress on greenhouse and field experiments with P. usgae to evaluate it as a biopesticide. I serve as committee member on his Ph.D. committee with Dr. Billy Crow (Chair). A putative Pasteuria species, strain R-1, which parasitizes a bacterial feeding nematode, Bursilla sp. was discovered in bermudagrass (Cynodon sp.) field plots at the FLREC in Davie, FL. This strain of Pasteuria was used to create a suppressive soil by continuously adding >500,000 Bursilla sp. every two weeks to a soil sample from the field where the isolate had been identified. R-1 was distinguished from other described species of Pasteuria using ultrastructure of the mature endospores and comparisons of genes encoding 16S rRNA. This is the first report of sustained in vivo culture of an isolate of Pasteuria on a bacterivorus nematode. We are working on the description of this prokaryote and plan to use it as a comparative genomic model with other Pasteuria species that attack plant-parasitic nematodes. I also serve on the Ph. D. committee of Mr. Joey Orajay, who is working on the project, "Development of molecular approaches towards a more sensitive detection and quantitative monitoring of Pasteuria sp. parasitizing ring nematodes in peanut (Arachis hypogea L.). Ring nematodes can also be problematic in turf and ornamentals. The genus Bursaphelenchus currently comprises about 100 described species but is mainly known in connection with the pine wood nematode, Bursaphelenchus xylophilus. Whereas most of the known Bursaphelenchus species are mycetophagous, B. xylophilus can be either mycetophagous or phytoparasitic causing great economic loss of susceptible pine trees in Asia and Portugal. The red ring or coconut palm nematode, B. cocophilus, is the only Bursaphelenchus known to be an obligate plant parasite, and the phytoparasitic mode of life causes the economically destructive red ring disease of coconut and African oil palms in the Lower Antilles and tropical America. A recent phylogenetic analysis showed that SSU, LSU and mtCOI gene sequences were useful for inferring phylogenetic relationships, and that the LSU dataset was the most informative across this genus. We have used this information as a starting point for further characterization of other members of this group leading to several descriptions and re-descriptions of Bursaphelenchus from as variety of different insects and environments. We are also working on the molecular phylogeny and systematics of other species of plant-feeding Aphelenchoidea to understand how this group may have evolved to parasitize plants. This includes members of the genera Aphelenchoides, Schistonchus, Ektaphelenchus, and others.
Publications
- Kanzaki, N., R. M. Giblin-Davis, Y. J. Cardoza, W. Ye, K. F. Raffa, and B. J. Center. 2008. Bursaphelenchus rufipennis n. sp. (Parasitaphelenchidae) and redescription of Ektaphelenchus obtusus (Ektaphelenchidae): associates from nematangia on the hind wings of Dendroctonus rufipennis (Coleoptera: Scolytidae). Nematology. 10:925-255.
- Hazir, C., R. M. Giblin-Davis, N. Keskin, W. Ye, N. Kanzaki, B. J. Center, S. Hazir, H. K. Kaya, and W. K. Thomas. 2007. Bursaphelenchus debrae n. sp. (Nematoda: Parasitaphelenchidae), an associate of the bee Halictus brunnescens in Turkey. Nematology. 9:777-789.
- Kanzaki, N., A. Fukiko, R. M. Giblin-Davis, K. Hata, K. Sone, K. Kiontke, and D. Fitch. 2008. Teratorhabditis synpapillata (Sudhaus 1985)(Rhabditida: Rhabditidae) is an associate of the red palm weevil, Rhynchophorus ferrugineus (Coleoptera: Curculionidae). Nematology. 10:207-218.
- Gulcu, B. Hazir, S., Giblin-Davis, R. M., Ye, W., Kanzaki, N., Mergen, H., Keskin, N., and Thomas, W. K. 2008. Molecular variability of Schistonchus caprifici from Ficus carica in Turkey. Nematology. 10:639-649.
- Zhao, Z. Q., Ye, W., Giblin-Davis, R. M., Li, D. M., Thomas, W. K., Davies, K. A., and Riley, I. T. 2008. Morphological and molecular analysis of six aphelenchoidoids from Australian conifers and their relationship to Bursaphelenchus (Fuchs, 1937). Nematology. 10:663-678.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Belonolaimus longicaudatus (sting nematode) is a serious problem on bermudagrass, a common warm-season turfgrass, in Florida. In addition, there are several other genera of plant-parasitic nematodes that cause damage to turf. The cancellation of organophosphate nematicides necessitates that new management tools be identified for use on sports turf. Three experimental formulations of Avermectin alone and in combination with HERITAGE TL were evaluated at about four and 8 weeks after the first application to determine if they suppress sting nematodes and/or improve plant performance relative to untreated controls (with and without sting nematode inoculation) and a commercial standard organophosphate nematicide (Nemacur) which was applied only once. The materials were applied twice for the 8 week trial (at the start and at 4 weeks). Under the conditions of this experiment, none of the compounds or combinations significantly suppressed sting nematode populations relative to the
Nemacur control or standard controls at 4 weeks. At 8 weeks, the sting counts had increased significantly and were equal to all of the test compounds and combinations of treatments, including Nemacur suggesting that this material had only been effective in the first 4 weeks. The experimental formulations of Avermectin alone and in combination with HERITAGE TL had no significant effects on the plant performance indicators (shoot and root dry weight) that were evaluated for the FX-313 St. Augustinegrass test plants. The genus Bursaphelenchus currently comprises about seventy recognized species but is mainly known in connection with the pine wood nematode, Bursaphelenchus xylophilus. Whereas most of the known Bursaphelenchus species are mycetophagous, B. xylophilus can be either mycetophagous or phytoparasitic causing great economic loss of susceptible pine trees in Asia and Portugal. The red ring or coconut palm nematode, B. cocophilus, is the only Bursaphelenchus known to be an
obligate plant parasite, and the phytoparasitic mode of life causes the economically destructive red ring disease of coconut and African oil palms in the Lower Antilles and tropical America. A phylogenetic analysis using DNA sequences of the nuclear small and large subunit ribosomal RNA genes and mitochondrial cytochrome oxidase subunit I was performed on representatives from 37 isolates of 20 Bursaphelenchus species encompassing much of the known biological diversity in this genus. Phylogenetic analyses using several methods of inference (NJ and MP for single loci and NJ, MP, ML and Bayesian for combined loci) were largely congruent. Phylogenetic analysis revealed B. abruptus as the sister to the other investigated Bursaphelenchus species and significant support was obtained for a large number of monophyletic groups which were consistent with morphological and life history variation in the genus. While SSU, LSU and mtCOI gene sequences are useful for inferring phylogenetic
relationships in this analysis, the LSU dataset was the most informative across this genus.
PARTICIPANTS: Collaborators: Barbara J. Center, FLREC, University of Florida, Maintains nematode cultures; Natsumi Kanzaki, Taxonomy & Ecology Forest Pathology Laboratory, Japan, Helps with Bursaphelenchus projects; Weimin Ye, North Carolina Department of Agriculture & Consumer Services, Helps with molecular phylogeny; W. Kelley Thomas, Hubbard Genomics Center, University of New Hampshire, Advises.
Impacts
Plant-parasitic nematodes cause serious damage to turfgrass and ornamentals. Postplant nematicides have been used for the management of phytoparasitic nematodes in turf for more than 20 years. These chemicals pose health and environmental risks requiring the development of alternative strategies such as biological control. Pasteuria bacteria and biorational compounds may have potential for postplant management of phytoparasitic nematodes in perennially managed turf ecosystems. Development of new strategies for postplant management of nematodes will be beneficial to sustained maintenance of turf and ornamentals in the landscape.
Publications
- Luc, J. E., W. T. Crow, J. L. Stimac, J. B. Sartain, and R. M. Giblin-Davis. 2006. Influence of Belonolaimus longicaudatus on nitrate leaching in turf. Journal of Nematology. 38:461-465.
- Ye, Weimin, R. M. Giblin-Davis, H. Braasch, K. Morris, and W. K. Thomas. 2007. Phylogenetic relationships among Bursaphelenchus species (Nematoda: Parasitaphelenchidae) inferred from nuclear ribosomal and mitochondrial DNA sequence data. Molecular Phylogenetics and Evolution. 43:1185-1197.
- Luc, J. E., W. T. Crow, J. L. Stimac, J. B. Sartain, and R. M. Giblin-Davis. 2007. Effects of Belonolaimus longicaudatus management and nitrogen fertility on turf quality of golf course fairways. Journal of Nematology. 39: 62-66.
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Progress 10/01/05 to 09/30/06
Outputs
Belonolaimus longicaudatus is a serious problem on bermudagrass, a common warm-season turfgrass, in Florida. In addition, there are several other genera of plant-parasitic nematodes that cause damage to turf. The cancellation of organophosphate nematicides necessitates that new management tools be identified for use on sports turf. The use of entomopathogenic nematodes (EPNs) has been suggested as one possible alternative. Results from several experiments evaluating the efficacy of EPNs at managing plant-parasitic nematodes on turfgrasses and improving turf performance were conducted at various locations throughout the state of Florida over the course of a decade and were published this year (see publications). Basically, we concluded that because in most trials EPNs had no effect on plant-parasites or were so inconsistent in their results, EPNs are not acceptable alternatives to fenamiphos by most turf managers in Florida at this time. The genus Belonolaimus (Sting
nematodes) currently comprises nine species of agriculturally important ectoparasitic nematodes. The D2/D3 of the large subunit (LSU) and ITS regions of rDNA from 33 Florida populations of three nominal Belonolaimus species were sequenced and subjected to phylogenetic analysis to develop an evolutionary framework for interpreting phenotypic differences as they relate to the taxonomy of the genus (see publications). None of the three nominal species (B. longicaudatus, B. euthychilus, and B. gracilis) appeared to be monophyletic. Three major clades of B. longicaudatus exhibited discernable, overlapping, geographic foci from east to west across Florida. We were unable to identify suites of morphological/morphometric character states that discriminated between the molecular-derived clades of B. longicaudatus. The large number autapomorphies for the relatively conserved D2/D3 region both between and within the nominal species reinforces previous observations that the genus Belonolaimus is
far more complex than currently recognized. A putative Pasteuria species, strain R-1, which is an obligately endoparasitic gram-positive prokaryote that parasitizes a bacterial feeding nematode, Bursilla sp. was discovered in bermudagrass (Cynodon sp.) field plots at the Fort Lauderdale Research and Education Center in Davie, FL. This strain of R-1 Pasteuria was used to create a suppressive soil by continuously adding >500,000 Bursilla sp. every two weeks to a soil sample from the field where the isolate had been identified. R-1 was distinguished from other described species of Pasteuria using ultrastructure of the mature endospores and comparisons of genes encoding 16S rRNA. Development and sporogenesis is similar to other nematode-specific Pasteuria. This is the first report of sustained in vivo culture of an isolate of Pasteuria on a bacterivorus nematode. We are working on the description of this prokaryote and plan to use it as a comparative genomic model with other Pasteuria
species that attack plant-parasitic nematodes.
Impacts
Plant-parasitic nematodes cause serious damage to turfgrass and ornamentals. Postplant nematicides have been used for the management of phytoparasitic nematodes in turf for more than 20 years. These chemicals pose health and environmental risks requiring the development of alternative strategies such as biological control. Pasteuria bacteria and biorational compounds may have potential for postplant management of phytoparasitic nematodes in perennially managed turf ecosystems. Development of new strategies for postplant management of nematodes will be beneficial to sustained maintenance of turf and ornamentals in the landscape.
Publications
- Crow, W. T., D. L. Porazinska, R. M. Giblin-Davis, and P. S. Grewal. 2006. Entomopathogenic nematodes are not alternative to fenamiphos for management of plant-parasitic nematodes on golf courses in Florida. Journal of Nematology. 38: 52-58.
- Gozel, U., B. Adams, K. Nguyen, R. Inserra, R. Giblin-Davis, and L. Duncan. 2006. A phylogeny of Belonolaimus populations in Florida inferred from DNA sequences. Nematropica. 36:149-165.
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Progress 10/01/04 to 09/30/05
Outputs
Belonolaimus longicaudatus is a serious problem on bermudagrass, a common warm-season turfgrass, in Florida. In addition, there are several other genera of plant-parasitic nematodes that cause damage to turf. The cancellation of organophosphate nematicides necessitates that new management tools be identified for use on sports turf. The use of entomopathogenic nematodes (EPNs) has been suggested as one possible alternative. Several experiments evaluating the efficacy of EPNs at managing plant-parasitic nematodes on turfgrasses and improving turf performance were conducted at various locations throughout the state of Florida over the course of a decade. In different experiments, different EPN species were tested against different species of plant-parasitic nematodes. Separate experiments evaluated multiple rates of EPNs, multiple applications, compared different EPN species, and compared single EPN species against multiple species of plant-parasitic nematodes. In a few
trials EPNs were associated with reductions in certain plant-parasite species, but were associated with increases in other trials. In most trials EPNs had no effect on plant-parasites. Because EPNs were so inconsistent in their results, we conclude that EPNs are not acceptable alternatives to fenamiphos by most turf managers in Florida at this time. The genus Bursaphelenchus currently comprises about seventy recognized species but is mainly known in connection with the pine wood nematode, Bursaphelenchus xylophilus. Whereas most of the known Bursaphelenchus species are mycetophagous, B. xylophilus can be either mycetophagous or phytoparasitic causing great economic loss of susceptible pine trees in Asia and Portugal. The red ring or coconut palm nematode, B. cocophilus, is the only Bursaphelenchus known to be an obligate plant parasite, and the phytoparasitic mode of life causes the economically destructive red ring disease of coconut and African oil palms in the Lower Antilles and
tropical America. Current understanding of relationships within the genus Bursaphelenchus is based mainly on analysis of morphological features, and it has been argued that Bursaphelenchus may be an uneasy assemblage of diverse species united by convergent characters. Therefore, a phylogenetic analysis using DNA sequences of the nuclear small and large subunit ribosomal RNA genes and mitochondrial cytochrome oxidase subunit I was performed. The analysis included representatives from 37 isolates of 20 Bursaphelenchus species encompassing much of the known biological diversity in this genus. Phylogenetic analyses using several methods of inference were largely congruent. Phylogenetic analysis revealed B. abruptus as the basal taxon among the investigated Bursaphelenchus species and significant support was obtained for a large number of monophyletic groups which were consistent with morphological and life history variation in the genus. While SSU, LSU and mtCOI gene sequences are useful
for inferring phylogenetic relationships in this analysis, the LSU dataset was the most informative across this genus.
Impacts
Plant-parasitic nematodes cause serious damage to turfgrass and ornamentals. Postplant nematicides have been used for the management of phytoparasitic nematodes in turf for more than 20 years. These chemicals pose health and environmental risks requiring the development of alternative strategies such as biological control. Pasteuria bacteria and biorational compounds may have potential for postplant management of phytoparasitic nematodes in perennially managed turf ecosystems. Development of new strategies for postplant management of nematodes will be beneficial to sustained maintenance of turf and ornamentals in the landscape.
Publications
- Griffith, R., R. M. Giblin-Davis, P. K. Koshy, and V. K. Sosamma. 2005. Chapter 13. Nematode parasites of coconut and other palms. In: Plant parasitic nematodes in subtropical and tropical agriculture, 2nd edition. [M. Luc, R. Sikora, and J. Bridge, eds.]. CABI Publishing. Pp. 493-527.
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Progress 10/01/03 to 09/30/04
Outputs
Belonolaimus longicaudatus is a serious problem on bermudagrass, a common warm-season turfgrass, in Florida. The cancellation of organophosphate nematicides necessitates that new management tools be identified for use on sports turf. Postplant application of 1,3-dichloropropene (1,3-D) on bermudagrass was evaluated for management of B. longicaudatus on golf course fairways and driving ranges. A series of experiments were conducted to evaluate the effectiveness of 1,3-D in reducing population densities of B. longicaudatus, and enhancing bermudagrass recovery from nematode damage. Seven experiments compared densities of B. longicaudatus, and turf performance, in plots treated with1,3-D to untreated plots 4 weeks after treatment. In two other experiments, population densities of B. longicaudatus and turf performance in plots treated with 2 rates of 1,3-D were compared with untreated and fenamiphos treated plots 2, 4, 8, and 12 weeks after treatment. A final experiment,
compared population densities of B. longicaudatus and turf performance in plots treated with 1,3-D with untreated plots 4 and 8 weeks after treatment. 1,3-Dichloropropene injected at 46.8 liters/ha was effective in reducing population densities of B. longicaudatus, and improving bermudagrass performance when other factors were not limiting. Postplant injection of 1,3-D could be a useful management tool for many sports turf applications. Phytotoxicity was minimal and was within the tolerance of most turf managers. Taxonomically relevant characteristics of a fastidiously Gram-positive, obligately endoparasitic prokaryote (strain S-1) that uses the phytoparasitic sting nematode, Belonolaimus longicaudatus as its host were reviewed. 16S rDNA sequence similarity (>93%) confirmed its congeneric ranking with other Pasteuria species and strains from nematodes and cladocerans and corroborated morphological, morphometric, and host range evidence suggesting a novel taxon. The 16S rDNA sequence
of strain S-1 has greatest similarity (96%) to the 16S rDNA sequences of both P. penetrans from root-knot nematodes (Meloidogyne spp.) and the recently reported strain of Pasteuria isolated from the soybean cyst nematode Heterodera glycines. Because the obligately endoparasitic nature of prokaryotes in the genus Pasteuria prevents isolation of definitive type strains, strain S-1 was proposed as Candidatus Pasteuria usgae sp. nov.
Impacts
Plant-parasitic nematodes cause serious damage to turfgrass and ornamentals. Postplant nematicides have been used for the management of phytoparasitic nematodes in turf for more than 20 years. These chemicals pose health and environmental risks requiring the development of alternative strategies such as biological control. Pasteuria bacteria and biorational compounds may have potential for postplant management of phytoparasitic nematodes in perennially managed turf ecosystems. Development of new strategies for postplant management of nematodes will be beneficial to sustained maintenance of turf and ornamentals in the landscape.
Publications
- Brito, J. A., Preston, J. F., Dickson, D. W., Giblin-Davis, R. M., Williams, D., Aldrich, H. C., and Rice, J. D. 2003. Temporal formation and immunolocalization of an endospore surface epitope during Pasteuria penetrans sporogenesis. Journal of Nematology. 35: 278-288.
- Crow, W. T., Giblin-Davis, R. M., and Lickfeldt, D. W. 2003. Management of Belonolaimus longicaudatus on established bermudagrass fairways using 1,3-Dichloropropene. Journal of Nematology, 35:331.
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