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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT & EVALUATION OF BIOLOGICAL CONTROL AGENTS FOR INVASIVE SPECIES THREATENING THE EVERGLADES & OTHER NATURAL AND MANANGED SYSTEMS

Location: Invasive Plant Research Laboratory

Title: Establishment, population increase, spread, and ecological host range of Lophodiplosis trifida (Diptera: Cecidomyiidae), a biological control agent of the invasive tree Melaleuca quinquenervia (Myrtales:Myrtaceae).

Authors
item Pratt, Paul
item Rayamajhi, Min
item Tipping, Philip
item Center, Ted -
item Wright, Susan
item Purcell, Matthew -

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 31, 2013
Publication Date: September 15, 2013
Citation: Pratt, P.D., Rayamajhi, M.B., Tipping, P.W., Center, T.D., Wright, S.A., Purcell, M.F. 2013. Establishment, population increase, spread, and ecological host range of Lophodiplosis trifida (Diptera: Cecidomyiidae), a biological control agent of the invasive tree Melaleuca quinquenervia (Myrtales:Myrtaceae). Environmental Entomology. 42(5):925-935.2013.

Interpretive Summary: The Australian tree Melaleuca quinquenervia (Cav.) Blake is an invasive weed in wetland systems of Florida, USA. A biological control program targeting M. quinquenervia has culminated in the release of the gall forming midge Lophodiplosis trifida Gagné (Cecidomyiidae). Populations of the introduced herbivore readily established at all 24 release sites across the weed’s range in Florida and there was no evidence that founding colony size (100, 2000, or 6000 adults) influenced herbivore establishment or local population growth rates. Landscape level spread of L. trifida from release sites averaged nearly 6 km/yr, ranging as high as 14.4 km/yr. Gall distribution within trees was affected by plant height as attack rates were greater in lower versus higher portions of the M. quinqueneriva canopy. Pre-release host range testing predicted that L. trifida oviposits indiscriminately on test plant species but does not complete development on any of the test species, including other congeners present in Florida. To test the predictability of these host range tests, L. trifida was released in a common garden consisting of 18 test plant species that were interplanted with M. quinquenervia. Plant species postulated to be at risk experienced no gall development by L. trifida while intermingled M. quinquenervia trees supported 704.8 (±158.5) galls per plant. Historically, many introduced Cecidomyiidae have limited effect on plant performance of target weeds due to recruitment of native parasitoids that disrupt biological control efficacy. In contrast to this trend, there has been no evidence to date that parasitoids are exploiting L. trifida in Florida.

Technical Abstract: The Australian tree Melaleuca quinquenervia (Cav.) Blake is an invasive weed in wetland systems of Florida, USA. A biological control program targeting M. quinquenervia has culminated in the release of the gall forming midge Lophodiplosis trifida Gagné (Cecidomyiidae). Populations of the introduced herbivore readily established at all 24 release sites across the weed’s range in Florida and there was no evidence that founding colony size (100, 2000, or 6000 adults) influenced herbivore establishment or local population growth rates. Landscape level spread of L. trifida from release sites averaged nearly 6 km/yr, ranging as high as 14.4 km/yr. Gall distribution within trees was affected by plant height as attack rates were greater in lower versus higher portions of the M. quinqueneriva canopy. Pre-release host range testing predicted that L. trifida oviposits indiscriminately on test plant species but does not complete development on any of the test species, including other congeners present in Florida. To test the predictability of these host range tests, L. trifida was released in a common garden consisting of 18 test plant species that were interplanted with M. quinquenervia. Plant species postulated to be at risk experienced no gall development by L. trifida while intermingled M. quinquenervia trees supported 704.8 (±158.5) galls per plant. Historically, many introduced Cecidomyiidae have limited effect on plant performance of target weeds due to recruitment of native parasitoids that disrupt biological control efficacy. In contrast to this trend, there has been no evidence to date that parasitoids are exploiting L. trifida in Florida.

Last Modified: 10/21/2014
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