Fergusonina turneri/Fergusobia quinquenerviae (Diptera: Fergusoninidae/Nematoda: Tylenchida: Sphaerulariidae, a Bud-Gall Fly and its obligate nematode released for the Australian paperbark tree, Melaleuca quinquenervia

Authors: Center, Ted; DAVIES, K - University Of South Australia; GIBLIN-DAVIS, R - University Of Florida; Pratt, Paul; PURCELL, M - Australian Biological Control Laboratory, ARS; Scheffer, Sonja; TAYLOR, G - University Of South Australia; Wright, Susan

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/1/2012
Publication Date: 1/1/2013
Citation: Center, T.D., Davies, K., Giblin-Davis, R., Pratt, P.D., Purcell, M., Scheffer, S.J., Taylor, G., Wright, S.A. 2013. Fergusonina turneri/Fergusobia quinquenerviae (Diptera: Fergusoninidae/Nematoda: Tylenchida: Sphaerulariidae, a Bud-Gall Fly and its obligate nematode released for the Australian paperbark tree, Melaleuca quinquenervia. Meeting Abstract. FHTET-2012-07/pg 119.

Interpretive Summary: The gall fly Fergusonina turneri and the nematode Fergusobia quinquenerviae form a mutualistic association on Melaleuca quinquenervia, an Australian tree that has invaded south Florida. Together they form multi-locular galls that compromise meristems thereby curtailing growth and reproduction of the targeted plant. Flies oviposit and nemaposit into vegetative and reproductive M. quinquenervia buds. Nematodes initiate cedidogenesis producing hypertrophied tissue prior to fly egg hatch. The maggots then feed on the primed nutrient-rich tissue while presumably inducing further enlargement of the galls. Meanwhile, the parthenogenetic nematodes produce a second generation of amphimictic individuals. The mated female nematodes invade the hemocoel of fully grown female (3rd instar) fly larvae. The fly pupates and the female nematodes produce juveniles that invade the rudimentary ovaries of the developing female flies. The adult fly then emerges from the gall carrying juvenile nematodes in their ovaries. All female flies contain nematodes, which are deposited in buds during oviposition allowing the cycle to begin anew. Molecular analyses of related Melaleuca species and host range studies proved this fly-nematode combination to be specific to M. quinquenervia. A permit for their release as biological control agents was subsequently granted. They were released in south Florida beginning in 2005 and temporarily established, but disappeared completely after about 3 generations. To date, these two agents have not established self-sustaining field populations in Florida. The more recent release and establishment of Lophydiplosis trifida, a gall-forming midge, produces similar pathology thus precluding the need for the fly/nematode combination. Nonetheless, this is the first time that a mutualistic combination of two agents has been approved and attempted for use in a biological control program.

Technical Abstract: The gall fly Fergusonina turneri and the nematode Fergusobia quinquenerviae form a mutualistic association on Melaleuca quinquenervia, an Australian tree that has invaded south Florida. Together they form multi-locular galls that compromise meristems thereby curtailing growth and reproduction of the targeted plant. Flies oviposit and nemaposit into vegetative and reproductive M. quinquenervia buds. Nematodes initiate cedidogenesis producing hypertrophied tissue prior to fly egg hatch. The maggots then feed on the primed nutrient-rich tissue while presumably inducing further enlargement of the galls. Meanwhile, the parthenogenetic nematodes produce a second generation of amphimictic individuals. The mated female nematodes invade the hemocoel of fully grown female (3rd instar) fly larvae. The fly pupates and the female nematodes produce juveniles that invade the rudimentary ovaries of the developing female flies. The adult fly then emerges from the gall carrying juvenile nematodes in their ovaries. All female flies contain nematodes, which are deposited in buds during oviposition allowing the cycle to begin anew. Molecular analyses of related Melaleuca species and host range studies proved this fly-nematode combination to be specific to M. quinquenervia. A permit for their release as biological control agents was subsequently granted. They were released in south Florida beginning in 2005 and temporarily established, but disappeared completely after about 3 generations. To date, these two agents have not established self-sustaining field populations in Florida. The more recent release and establishment of Lophydiplosis trifida, a gall-forming midge, produces similar pathology thus precluding the need for the fly/nematode combination. Nonetheless, this is the first time that a mutualistic combination of two agents has been approved and attempted for use in a biological control program.