Establishment, Population Increase, Spread, and Ecological Host Range ofLophodiplosis trifida(Diptera: Cecidomyiidae), a Biological Control Agent of the Invasive TreeMelaleuca quinquenervia(Myrtales: Myrtaceae)

Abstract

The Australian tree Melaleuca quinquenervia (Cavanilles) Blake is an invasive weed in wetland systems of Florida. A biological control program targeting M. quinquenervia has resulted in the release of the gall forming midge Lophodiplosis trifida Gagné (Diptera: 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, 2,000, or 6,000 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. Prerelease 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 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 because of 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.

The role of ecological availability and host plant characteristics in determining host use by the bogus yucca moth Prodoxus decipiens

“…Garrido et al , ). Perhaps some of the best examples come from studies of host ranges of intentionally released biocontrol agents or unintentionally introduced insects that have been surveyed for use of novel host plant species in the introduced range (Pearse et al , ; Pratt et al , ). The number of insect species that are able to colonise and persist on new host plant species suggests that geographic range is an important component in determining host use (Agosta, ).…”

Within-plant distribution of theMelaleuca quinquenerviabiological control agentLophodiplosis trifida

“…Populations established at all release locations and, by 2010, L. trifida had dispersed far beyond original release sites (Pratt et al, 2013).…”

The influence of two wildfires and biological control agents on the population dynamics of Melaleuca quinquenervia in a seasonally inundated wetland

“…The third agent was Lophidoplosis trifida Gagne (Diptera: Cecidomyiidae), a galling fly that was released in 2008 (Purcell et al 2007). It also established readily and spread quickly, and its gall-forming activities can reduce sapling height by 10%, leaf biomass by 42%, woody biomass by 42.7%, and root biomass by 30.3% (Pratt et al 2013;Tipping et al 2016).…”