Submitted to: Germplasm Release
Publication Type: Germplasm Release
Publication Acceptance Date: 1/20/2003
Publication Date: 11/20/2003
Citation: Buckingham, G.R., Goolsby, J., Pemberton, R.W. Proposed field release of the australian cataclysta camptozonale (hampson) (lepidoptera: crambidae), a defoliator of australian old world climbing fern, lygodium microphyllum, in florida. Germplasm Release.
Interpretive Summary: Old World climbing fern is an invasive weed native to the Old World tropics which naturalized in Florida during the 1960's. During the 1990's, the weed developed explosive populations and increased dramatically in density and is spreading through much of southern Florida and into central Florida. The weed often completely dominates the natural areas that it invades, greatly reducing and even eliminating most of the native plants present, effectively destroying these communities. Old World climbing fern is threatening many of the most valued natural areas in Florida including Everglades National Park, Big Cypress and Loxahatchee National Wildlife Refuges. It is also a pest of horticultural crops and residential areas on moist soils. Herbicidal control of the weed is an expensive, temporary solution which can enhance the growth of the weed because it kills competing vegetation. A biological control project was begun in 1998 in order to find and implement suitable natural enemies of the fern in Florida. The first insect to be intensively studied is the Australian pyralid moth, Cataclysta camptozonale. The moth is known to attack only two species of Lygodium in its native Australia, and was never found on the ferns or other plants in habitats where it was common on Lygodium microphyllum. The moth was evaluated potential biological control agent for the weed at the USDA-ARS Australia Biological Control Laboratory and by USDA-ARS scientists at the Florida Biological Control Quarantine Laboratory. Sixty six plant species were tested against the moth. The test plants included 57 fern and fern allies belonging to 23 different families, the plants moth likely to be acceptable hosts of the moth, and 9 important Florida crop plants in 8 different families. The moth was confirmed to be an extremely narrow specialist accepting only a few Lygodium ferns. It is unable to develop on any of the four Caribbean Lygodium species. It can develop on the single North American Lygodium, L. palmatum, but it is not expected to contact or harm this fern because the moth is a tropical species whereas this fern is a temperate species. The inability of the moth to survive freezing temperatures was confirmed by experiments. Although moths have been major biocontrol agents, most moths released for biological control them have not been. We cannot predict that release of this moth will successfully control the weed, because it is impossible to predict the population levels it will achieve. We can predict that L. microphyllum will continue to worsen where it has invaded and spread relatively unabated without a biological control agent. Even localized control by the moth would be welcome. Major defoliation of L. microphyllum by the moth was observed in the native habitat in Australia in the presence of natural enemies. A generation in the laboratory requires only one month. Without specialized natural enemies in Florida and with a new generation every month, there is potential for enormous population growth and significant defoliation. Cataclysta camptonozale is a safe and potentially effective control agent of L. microphyllum which is recommended for release and use against the most serious natural areas weed in Florida.
Technical Abstract: No technical abstract