2010 Annual Report
1a.Objectives (from AD-416)
Parkinsonia (Caesalpinioideae) was planted in Australia mainly as an ornamental and shade tree. The detrimental effects include its propensity to form dense, thorny, impenetrable thickets along drainage lines, depressions, and ephemeral wetlands. Investigations into the potential biological control began in 1983. Two insects from the Sonoran Desert Region, Rhinacloa callicrates and Mimosestes ulkei were released since 1989 and a third insect from Argentina, the seed-feeding bruchid, Penthobruchus germaini, in 1995. Additional agents are needed. Recent genetic studies indicating very old dispersal events of P. aculeata in South America, stimulated interest in survey work in this area. Previous native-range surveys conducted in Argentina and Paraguay by ARS researchers revealed the existence of two prospective geometrid moths, Eueupithecia cisplatensis (Prout) and Euacidalia sp
1b.Approach (from AD-416)
• Focus searches on warmer semi-arid areas that match target climates in Australia.
• Collect young living plants of P. aculeata for growing at the Hurlingham laboratory.
• Transport living geometrid specimen to the Hurlingham laboratory.
• Rear the specimens to adult.
• Initiate a lab colony on the living plants of P. aculeata.
• Collect data on life cycle and basic biology.
• Compile a list of related species that could be collected as young plants and grown in pots in the lab for host specificity testing.
• Collect and grow these plants.
• Conduct host specificity tests. Use no-choice test design. Attempt to obtain mating and oviposition on test plant species and P. aculeata control and record larval development.
• If direct oviposition on plants is not possible, transfer eggs onto leaves of various species and record larval development.
• Variations to host testing to be discussed with Dr Tim Heard.
• While collecting geometrids, collect, preserve and label other insect herbivores.
• If geometrids cannot be found, transfer effort into the survey of other herbivorous species.
• If any other species appear promising, attempt rearing and specificity testing within the possibility of the available resources.
• Keep herbarium specimens of plants from all sites visited.
• Keep data sheets of characteristics of sites visited.
• If appropriate, collect geometrids from neighbouring legumes when populations found on P. aculeata.
Studies were focused on the leaf-feeding moth Eueupithecia cisplatensis and the stem-galling midge Neolasioptera n. sp. Eueupithecia cisplatensis: Biology: there were four larval instars. The larval stage lasted 16.9 ± 3.1.days (mean ± SD; n = 21). Survival to the adult stage was 42 %. Host range: larval development no-choice tests were conducted on additional Leguminosae species. Besides P. aculeata, larval development was only registered on P. praecox. Additional field host data was obtained in two trips. No E. cisplatensis larvae were collected on Acacia, Parkinsonia or Prosopis species. On the contrary, 497 larvae were collected in 9 sites by beating on P. aculeata. A colony of E. cisplatensis is currently being raised to make a shipment to CSIRO quarantine facilities. Neolasioptera n. sp.: Phenology, distribution, density and field host range were studied. New findings: eggs, nymphs and adults of a mite were found on the stems of P. aculeata in six sites. Specimens were sent to ARS-Systematic Entomology Lab for identification.
Methods used for the monitoring of this subordinate project included periodical phone calls and E-mail exchanges with CSIRO Entomology, Indooroopilly, Australia. Progress reports were prepared and delivered to the funding agency.