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United States Department of Agriculture

Agricultural Research Service

Research Project: LYGODIUM BIOCONTROL INVESTIGATIONS

Location: Invasive Plant Research Laboratory

2013 Annual Report


1a.Objectives (from AD-416):
To discover and identify natural enemies of Lygodium in its native range, conduct host specificity testing on promising enemies, petitioning for the release of suitable biocontrol agents with the potential for controlling Lygodium, colonizing the agents, and monitoring their effects on the target weed and on non-target vegetation.


1b.Approach (from AD-416):
Research will be conducted in the Australian Biological Control Laboratory in Brisbane and in the Austral-Southeast Asian Region and will focus on the discovery and identification and prelimary host range testing of promising biological control agents. Full host specificity testing will be conducted in domestic quarantine, after which appropriate agents will be petition for release, then after permission to release is obtained, mass reared, colonized and then monitored to determine their establishment and potential impact on Lygodium and non-target vegetation.


3.Progress Report:

This research relates to in-house objectives: 3. Conduct faunistic and floristic inventories to discover natural enemies that may serve as biological control agents for target weeds including, but not limited to Brazilian pepper, lygodium, downy rose myrtle, skunk vine and Chinese tallow. Additional biological control agents will be sought for species for which some control has been achieved, including melaleuca; 4. Conduct risk analysis to determine environmental safety of new and existing potential biological control agents for weeds such as air potato, melaleuca, Brazilian pepper, lygodium, downy rose myrtle, Chinese tallow, waterlettuce and skunk vine; and 5. Release, establish, evaluate efficacy, and corroborate environmental safety of approved biological control agents and develop and distribute the technology to customers in order to expedite their adoption and deployment.

The focus of our Lygodium microphyllum research in Australia was placed on the collection of Musotiminae leaf-feeders for comparative lab studies to be undertaken in Florida and on the development of rearing techniques of the Bamaga stem borer to facilitate host range testing. South-east Asian exploration on Lygodium microphyllum focused on recollecting two insect species, the Lygodium sawfly Neostrombocerus albicomus and the pyralid moth, Lygomusotima stria. The sawfly was required by the USDA/ARS Invasive Plant Research Lab (IPRL) for colonisation so that final testing could be completed on the Caribbean Lygodium test plant species. Large numbers of larvae were collected from sites in Thailand in December. New stocks of L. stria were required to boost the laboratory colony at IPRL for host range testing after disease outbreaks reduced its size. Collections were made in eastern Thailand and Singapore and hand carried to IPRL. Field data recorders were retrieved from Hong Kong; temperature and humidity data will be used to improve quarantine and glasshouse rearing conditions of all stem-boring pyralids from Asia and Australia. A new borer site was located on mainland China.

Research on biological control of Lygodium microphyllum in Florida has progressed on several fronts. Neomusotima conspurcatalis continues to increase its range and has dispersed beyond initial predictions. We have initiated several new studies to look at the potential impacts of N. conspurcatalis of field populations of L. microphyllum. Additionally, Floracarus perrepae, a leaf-galling mite that was released in 2010 and 2011, has also been found in areas well beyond the established release sites. The apparent establishment success of both agents is a boon to future research of musotiminine crambid moths as well as investigations that focus on multi-trophic interactions amongst L. microphyllum consumers. Within quarantine, Lygomusotima stria is being reared and maintained and we have made progress in regards to host range testing as well as cold tolerance. Additional host plants were acquired in 2013 when a scientist from IPRL collected Lygodium volubile and L. micans from Jamaica, which will be used in host range testing for L. stria and Neostrombocerus albicomus. Efforts continue to locate and obtain L. cubense, but so far to no avail. The Lygodium sawfly, Neostrombocerus albicomus was recollected from Thailand in 2012 and we have successfully reared three generations through in quarantine.


Last Modified: 7/22/2014
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