|Dray, F Allen|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2006
Publication Date: 12/5/2006
Citation: Center, T.D., Pratt, P.D., Tipping, P.W., Rayamajhi, M.B., Van, T.K., Wineriter, S.A., Dray Jr., F.A., Purcell, M. Field colonization, population growth, and dispersal of Boreioglycaspis melaleucae Moore, a biological control agent of the invasive tree Melaleuca quinquenervia (Cav.) Blake. Biological Control. 39:363-374. 2006.
Interpretive Summary: Diversion of water flow from the Everglades during the 1950s allowed exotic species to invade previously undisturbed, pristine habitats. Foremost amongst these invaders was the Australian melaleuca tree which usurped a half million acres. A massive effort is underway to restore the natural water flow, but this will not eliminate melaleuca, which has indelibly modified many critical habitats making them more vulnerable to wildfires. Melaleuca has also increased soil elevations creating drier conditions. Removal of these pernicious trees is therefore a necessary part of Everglades restorations. Biological control is being implemented to assist in this effort by hampering the trees ability to re-establish in areas where it has been removed. Plant-feeding insects imported from Australia are being released after long-term testing ensures that they will not harm other plants. Most recently, a psyllid or plant louse was released to compliment the earlier release of a weevil. The psyllid has now established throughout the Everglades regions and is assisting in the control of melaleuca.
Technical Abstract: Invasion of native plant communities by the Australian paperbark tree (“melaleuca”), Melaleuca quinquenervia, complicates restoration of the Florida Everglades. Biological control, within the context of a comprehensive management program, offers a means to suppress regeneration after removal of existing trees and a mechanism to forestall reinvasion. To meet this need, a biological control program commenced during 1997 upon the release of an Australian weevil (Oxyops vitiosa Pascoe). Release of a second biological control agent, the melaleuca psyllid (Boreioglycaspis melaleucae Moore), followed during Feb. 2002 at field sites containing mixed age-class melaleuca stands or coppicing stumps. Each site was inoculated with 7000-10000 adult psyllids, with one exception at another site where 2000 nymphs were released on seedlings the following December. Psyllid populations established everywhere irrespective of colony source, site conditions, or the quantity released, although numbers released and, to a lesser degree, colony age influenced the numbers of colonies produced. One site, comprised mainly of coppicing stumps, contained 3.3 million psyllids/ha within 3 months after release. Less than 1% of the coppices at a similar site harbored psyllid colonies 2 mo. after release (May 2002), but this rose to 75% in October then to 100% by December. The census population exceeded 715,000 adults and nearly 11 million nymphs by late January 2003. Psyllid populations dispersed 2.2 to 10.0 km/yr, with the slower rates in dense, continuous melaleuca stands and faster rates in fragmented stands. Over 1 million psyllids had been redistributed to 100 locations as of December 2005. This species now occurs throughout the range of melaleuca in south Florida due to natural range expansion as well as anthropogenic dissemination.