|SIPES, BRENT - University Of Hawaii|
|Matsumoto Brower, Tracie|
|MELLO, JOAQUIN - Hawaii Department Of Land And Natural Resources|
Submitted to: Nematropica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2015
Publication Date: 12/1/2015
Citation: Myers, R.Y., Sipes, B.S., Matsumoto Brower, T.K., Mello, C.L., Mello, J.S. 2015. Occurrence and distribution of Heterorhabditid populations in the Hawaiian Islands. Nematropica. 45:198-207.
Interpretive Summary: Insect-parasitic nematodes can be effective biological control agents against some insect pests. Their ease of application and lack of toxicity to humans, other animals, and the environment make insect-parasitic nematodes a desirable component in an integrated pest management program. With limited sustainable methods for insect control, growers need additional options. Currently regulatory laws exist that restrict the importation of Heterorhabditis, a commercially available insect-parasitic nematode, into Hawaii. To build a case for the introduction of these organisms, a survey was conducted to document natural populations of Heterorhabditis in Hawaiian soils. Sequencing of a barcode gene confirmed two species of Heterorhabditis were collected on four of the five main Hawaiian Islands. Infectivity studies of wax moth larvae demonstrated that one species was highly virulent causing insect mortality within 2 days of inoculation. Additional studies are needed to test this Heterorhabditis species on other invasive insect pests plaguing Hawaii’s agricultural industry.
Technical Abstract: A survey of entomopathogenic nematodes (EPN) in the Hawaiian Islands recovered Heterorhabditis indica and previously undescribed Heterorhabditis species. Using Galleria bait, morbid larvae were recovered from 187 of the 275 samples collected within 100 m of the ocean. Entomopathogenic nematodes were recovered from 21% of morbid larvae. Heterorhabditis indica and Heterorhabditis spp. occurred in 7% and 8% of the total samples, respectively. Half of the heterorhabditids recovered were from the island of Kauai. Heterorhabditis indica was detected on all islands and Heterorhabditis spp. on all islands but Molokai. In filter paper bioassays, the Oahu strains of H. indica were the most infective EPN tested, causing 100% mortality of G. mellonella larvae within 48 hr after inoculation with 10 or more infective juveniles. Heterorhabditis was easily isolated from coastal areas of Hawaii.