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United States Department of Agriculture

Agricultural Research Service


Location: Crop Production and Protection

2011 Annual Report

1a. Objectives (from AD-416)
Objective 1: Discover, identify, and initiate the characterization of new biological control agents for targets, including, but not limited to, the weeds Melaleuca quinquenervia, Lygodium microphyllum, Casuarina spp., Paederia foetida, Rhodomyrtus tomentosa, Triadica sebifera and Hydrilla verticillata, and the psyllid pest, Diaphorina citri. Other weeds and insect pests that are invasive in the U.S. and native to Australia and/or Southeast Asia can become priority targets as required. Objective 2: Conduct preliminary field and laboratory research on natural enemies to assess efficacy and host-range to determine their potential for use as biological control agents. Assess results to prioritize potential agents for introduction into the United States. Expedite establishment of high-priority agents by collecting, rearing and shipping to U.S. collaborators for high priority target weeds, such as additional agents for M. quinquenervia. Objective 3: Conduct ecological studies on targets that identify the key regulatory factors in its native habitat and use this understanding to direct selection of agents.

1b. Approach (from AD-416)
Objective 1: Foreign exploration will be conducted in Australia and Southeast Asia for potential biological control agents of Melaleuca quinquenervia, Lygodium microphyllum, Casuarina spp., Paederia foetida, Rhodomyrtus tomentosa, Triadica sebifera and Hydrilla verticillata and additional weed targets as determined by ARS and stakeholders. Selection of search areas will be guided by the center of origin of the weed species (classical and molecular diagnostics), habitat diversity, climate matching, specific phenology and ecology of the targets, and consultation with local and foreign contacts. Objective 2: High priority agents identified in exploration will be further evaluated in laboratory and field studies. Studies will investigate the basic biology of the organism, seasonal phenology, impact on its host, and host range. Specific aspects of an agent’s biology such as critical temperature limits will be investigated. Objective 3: Field and laboratory studies will be conducted on target weed species which measure factors such as stand regeneration, seed production, biomass accumulation, litter fall, etc. Data will also be used to identify biological attributes that can be manipulated with biological control agents to affect control.

3. Progress Report
The gall midge Lophodiplosis indentata was the priority for research on the biological control of melaleuca, Melaleuca quinquenervia. Colonies were used to supply the IPRL quarantine facility in Gainesville. Seasonality of this insect was monitored in southeast Queensland for three years. The impact of interactions between L. indenata and the stem-galling relative L. trifida were studied. The defoliating moth Careades plana in north Queensland was collected for recolonisation attempts. Testing of the puff-ball gall former, “Sphaerococcus” ferrugineus has been suspended and will be resumed in late 2011. Cultures of the bud-weevil, Haplonyx multicolor, were destroyed when a decision was made in collaboration with IPRL colleagues to cease further evaluation of this non-specific insect. Research is underway to survey the abundance of Lygodium stem-boring pyralid moths, Ambia sp., at different times of the year to understand seasonal fluctuations in abundance. In 2010/2011, over 700 borer damaged stems and Ambia sp. pupae were collected and shipped/hand carried to ABCL quarantine in Brisbane. An F1 generation Ambia adult was obtained in quarantine for the first time. For the first time, borers were located in Australia, attacking L. microphyllum near Bamaga on Cape York, Queensland. Larvae of the defoliating moth Lygomusotima stria were collected in Singapore, shipped to ABCL, colonised, and subsequently transhipped to IPRL. Surveys of downy rose myrtle, Rhodomyrtus tomentosa, were conducted in China. Small amounts of damage caused by larvae of the flower/fruit and tip feeding Cosmopterigidae 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 (CAS) in Wuhan, Hubei Province. Specimens of Metharmostis sp. were imported into ABCL quarantine from two sites in Hong Kong from which adults and parasites were reared for taxonomic purposes. Several shipments of Metharmostis sp. were also made to the IPRL quarantine in Gainesville, Florida where a colony has been established and host range testing has been initiated. Sites in mainland China, Hong Kong and India were evaluated for demographic studies planned to commence in late 2011. Exploratory research continued on skunk vine, Paederia foetida, and Australian pine, Casuarina spp.; both plants are serious weeds in the United States, particularly Florida and Hawaii. Stem-boring moth larvae were collected from P. foetida in Hong Kong and shipped directly to IPRL quarantine in Fort Lauderdale. Cultures of a leaf -galling wasp, Selitrichodes sp., an undescribed leaf-galling midge, and a defoliating moth, Cryptophasa irrorata, are in culture at ABCL for evaluation as potential control agents of Casuarina spp. Collections of parasites of the Asian citrus psyllid, Diaphorina citri, were made in Yunnan China and Singapore and shipped to APHIS quarantine in Mission Texas were quarantine cultures of the Tamarixia radiata have been established.

4. Accomplishments

Last Modified: 10/17/2017
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