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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGICAL CONTROL OF MELALEUCA AND OTHER INVASIVE PLANTS

Location: Invasive Plant Research Laboratory

2011 Annual Report


1a.Objectives (from AD-416)
Develop safe and effective biological control agents of Melaleuca quinquenervia and other invasive weeds.


1b.Approach (from AD-416)
The following are the performance steps of a classical biological control investigation:

1. Survey and identify the pest's native range for list of herbivores that attack the pest plant.

2. Identify the best potential biocontrol agents based on field observations, preliminary lab tests, and information from local scientists.

3. Conduct preliminary host-range tests on most promising candidate in native country to obtain permission to import to U.S. quarantine.

4. Complete host-range tests in U.S. quarantine to ensure safety of the organism relative to local native plants, agricultural crops, and ornamental.

5. Petition Federal Technical Advisory Group for permission to release in the U.S. Also, obtain permission from necessary State agencies.

6. Culture agents that are approved to have sufficient numbers to release at field sites. Test release strategies to determine best method.


3.Progress Report

This project supports the in-house project objective 3: Conduct faunistic and floristic inventories to discover natural enemies that may serve as biological control agents for target weeds by surveying herbivores of Melaleuca and Rhodomyrtus, developing rearing methods and testing the host specificity of candidate agents in quarantine.

The Melaleuca pea-gall fly, Lophodiplosis indentata, was maintained from which five shipments were made to the Invasive Plant Research Laboratory quarantine in Gainesville. Host range testing of Sphaerococcus is ongoing and this insect appears to be highly specific. Surveys of Rhodomyrtus were conducted in China in June 2011. Little damage caused by larvae of the flower/fruit and tip feeding moth Metharmostis sp. were observed in Jiangxi, Guangdong and Guangxi provinces. Larvae of other flower/fruit feeding Lepidoptera were also collected and are being reared by collaborators at the Chinese Academy of Sciences in Wuhan, Hubei Province. In December 2010, 63 tips damaged by Metharmostis sp. and a pupa were imported into Australian Biological Control Lab quarantine from two sites in Hong Kong from which eight adults and 3 parasites were reared for taxonomic purposes. Sites in mainland China, Hong Kong and India were evaluated for demographic studies planned to commence in 2012. Samples of Rhodomyrtus were collected at most locations for chemical and genetic analyses.

Two decisions regarding the Melaleuca project were made in Dec 2010. .
1)Host range studies of Haplonyx were to be halted due to its similar use of three congeneric ornamental bottlebrush species. Tests of the number of generations of Haplonyx supported on Florida bottlebrush species, initiated in July 2009, were to be continued to an appropriate end point. Tests have been completed except for those on Melaleuca citrina as adults are long-lived. .
2)Quarantine research on Lophodiplosis indentata, a cecidomyiid or pea gall fly was to be initiated. Five foreign shipments of galls were received in quarantine between Jan 2011 and Jul 2011. A small colony was established from the first shipment but it did not survive past the second generation. The next two shipments were delayed in transit and no cecids survived the delays. The last two shipments have produced adults but not enough time has elapsed for a generation to complete development. L. indentata are easily colonized on Australian Melaleuca so colonization is expected on Florida Melaleuca. Expansion of the Rhodomyrtus project continued during fiscal year11. Four unknown herbivores collected in Hong Kong by Australian Biological Control Laboratory (ABCL) scientists and reared in Florida quarantine were submitted and identified to at least genus: Metharmostis new sp., Herminias sp., Mesophleps albilinella, and Eucyclodes albisparsa. Metharmostis sp. was selected as a prospective candidate for biological control. Metharmostis has been established and expanded twofold each generation. To date, second generation pupae continue to be collected as over 72 adults are already producing third generation eggs and larvae.


Last Modified: 10/30/2014
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