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United States Department of Agriculture

Agricultural Research Service

Research Project: Molecular Resources for the Improvement of Tropical Ornamental and Fruit Crops

Location: Tropical Plant Genetic Resources and Disease Research

Title: The hunt for Heterorhabditis in Hawaii

item Myers, Roxana
item Sipes, Brent
item Hollingsworth, Robert

Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: 7/2/2013
Publication Date: 12/31/2013
Citation: Myers, R., B.S. Sipes, R.G. Hollingsworth. 2013. The hunt for Heterorhabditis in Hawaii. Journal of Nematology. 45(4):306.

Interpretive Summary:

Technical Abstract: A survey was conducted to collect Heterorhabditis spp. in natural environments in Hawaiian soils. Quarantine laws currently prevent the importation of commercial isolates of Heterorhabditis into the State of Hawaii for biological control. Documenting natural populations would strengthen the case for the introduction of these organisms and could lead to the discovery of more virulent, better adapted tropical isolates. Previous surveys in Hawaii showed endemic Heterorhabditis populations exist primarily in coastal areas so collection sites at sea level were made. Soil was collected between 5 – 30 cm deep from beneath vegetation within 100 m of the shoreline. Soil samples were placed in a 473-cc plastic container and baited with six Galleria mellonella. After one week, morbid larvae were rinsed, placed on white traps, and monitored for emerging nematodes. Of 124 sites sampled, morbid larvae were recovered from 68 samples and 24% of these sites contained some type of entomopathogenic nematode based on morphological observation. PCR was conducted on single EPN specimens using primers to amplify the ITS regions. The resulting products were sequenced and the ITS rDNA sequences compared to existing entries in GenBank. Two specimens were confirmed to be Heterorhabditis indica. Further morphological and molecular analysis will be conducted on other specimens tentatively identified as new species of Heterorhabditis and Heterorhabditoides. Penetration and infectivity assays of promising isolates will aid in determining if these natural isolates are better adapted to tropical environments than current commercially available isolates.

Last Modified: 10/16/2017
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