|GUTIERREZ-COARITE, ROSEMARY - UNIVERSITY OF HAWAII|
|YONEISHI, NICOLE - UNIVERSITY OF HAWAII|
|MOLLINEDO, JAVIER - UNIVERSITY OF HAWAII|
|PULAKKATU-THODI, ISHAKH - UNIVERSITY OF HAWAII|
|WRIGHT, MARK - UNIVERSITY OF HAWAII|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/31/2017
Publication Date: 1/10/2018
Citation: Gutierrez-Coarite, R., Yoneishi, N., Mollinedo, J., Pulakkatu-Thodi, I., Wright, M., Geib, S.M. 2018. PCR-based gut content analysis to detect predation of Eriococcus ironsidei (Hemiptera: Eriococcidae) by Coccinellidae species in macadamia nut orchards in Hawaii. Journal of Economic Entomology. https://doi:10.1093/jee/toy019.
Interpretive Summary: Macadamia felted coccid, is an introduced and invasive pest species in Hawaii, primarily impacting macadamia nut trees. It was first found on the island of Hawaii in 2005. Macadamia felted coccid infests all above-ground parts of trees, including bark, stems and leaves, to feed and reproduce. This feeding can impact the growth and development of the tree, and reduce crop yield. One potential way to control this pest insect is to utilize existing predatory beetles to predate on the coccid pests to reduce damage. Currently, predatory behavior of beetles found in macadamia fields is not known, and due to the extremely small size of the coccid pest, visualization of predatory behavior is difficult in the field and lab. To screen predatory beetles found in macadamia nut fields in Hawaii for evidence of predation on macadamia nut coccid, a molecular test was developed to detect prey (coccid) DNA in a DNA extraction of whole body predator beetle. Analysis of beetles collected from macadamia orchards revealed predation by H.chalybeus, C.coeruleus, S.lividigaster, R.forestieri, and S.ruficeps on felted coccid. This study demonstrates that these beetles may play an important role in controlling the population of E.ironsidei, and these predators may be useful as biocontrol agents for felted coccid through maintenance of habitats to promote predatory beetle establishment.
Technical Abstract: Macadamia felted coccid, Eriococcus ironsidei (Williams) (Hemiptera: Eriococcidae) was first found infesting macadamia trees in the island of Hawaii in 2005. Macadamia felted coccid infests all above-ground parts of trees to feed and reproduce. Their feeding activity distorts and stunts new growth which causes yellow spotting on older leaves, and when population densities become high, branch dieback occurs. Different predatory beetles have been observed in macadamia nut trees infested by E.ironsidei, the most abundant were Halmus chalybeus, Curinus coeruleus, Scymnodes lividigaster, Rhyzobius forestieri, and Sticholotis ruficeps. To verify predation of E.ironsidei by these beetles, a molecular assay was developed utilizing species-specific primers to determine presence in gut content of predators. Using these primers for PCR analysis, wild predator beetles were screened for the presence of E.ironsidei DNA. Analysis of beetles collected from macadamia orchards revealed predation by H. chalybeus, C. coeruleus, S.lividigaster, R.forestieri, and S.ruficeps on E.ironsidei. This study demonstrates that these beetles may play an important role in controlling the population of E.ironsidei, and these predators may be useful as biocontrol agents for E.ironsidei.