Seed Wasp Project well underway - Update from Dr Ainsley Seago
(see also stories below)
A grower survey has been composed and has been distributed through Lucerne Australia; this will help direct upcoming fieldwork and ensure that this project accounts for the full diversity of lucerne seed cultivation practices.
Many growers have already volunteered to participate in sample submission for this project, as well as several seed cleaning operators.
LSW literature review has been completed and is currently being prepared for submission as a peer-reviewed publication. Major findings from the literature review include:
1. Mineral oil sprays are an effective oviposition control measure for the related pest species Bruchophagus felis.
2. Cultivation practices (clipback followed by bulk bee release for rapid pollination) prevent LSW from being a major pest in lucerne seed production regions of the US.
3. Among other seed-parasite chalcidoid wasps, the only effective pesticidal control is via systemic (whole-plant) take-up, not spray application.
4. For the ecologically similar seed parasitoid wasp Systole coriandri (coriander seed chalcid), 100% mortality can be achieved by storing seeds in paper envelopes over liquid nitrogen for 16-24 hours. This kills all larvae present within the seeds without affecting subsequent seed germination rate.
Glasshouse space has been reserved at OAI, two technical staff have been identified for work on this glasshouse component, and we are working with incoming graduate students to align their research work with participation in this study.
Lucerne plants from NSW have been collected and seedlings are currently sprouting.
A PCR test for LSW has been completed, including the identification and testing of appropriate primers for amplifying LSW DNA.
Plant viruses can cause significant economic losses in agriculture and some may pose biosecurity risks to lucerne production and seed exports.
The devastating Alfalfa Dwarf Disease (ADD), which involves a complex of five different aphid-transmitted viruses, was first reported from Argentina in 2010, causing significant yield losses and reduced seed production.
The RIRDC-funded project, ‘Potential exotic virus threats to lucerne seed production in Australia’ is seeking to provide assurance that alfalfa dwarf virus (ADV), a novel rhabdovirus found to be associated with ADD, is not present in Australia and to determine how best it can be prevented from reaching our shores.
Dr Ralf Dietzgen, Associate Professor in the Queensland Alliance for Agriculture and Food Innovation Institute at the University of Queensland is leading the project.
During the first year of research, project scientists developed a sensitive diagnostic test for detection of ADV in extracts of lucerne leaves. Field surveys of several South Australian lucerne seed paddocks using this test during 2015/16 failed to detect ADV. Selected lucerne paddocks used for hay production in Queensland and Victoria were also shown to be free of this exotic virus. Additional surveys are planned for 2016/17.
Alongside this work, the international research team is investigating the biology of ADV and interactions between the associated viruses, insect vectors, potential for seed transmission, and alternative crop and weed hosts. Selected Australian lucerne varieties are also being tested under field conditions in Argentina to identify potentially resistant lines.
“Based on the combined knowledge gathered in Australia and Argentina, we will conduct a detailed risk analysis and develop a biosecurity plan and integrated control measures for alfalfa dwarf disease,” Dr Dietzgen says. “This will place the Australian lucerne industry in an excellent position to protect lucerne from this exotic virus disease and increase certified seed exports to South America.”
The surveys also investigated the presence of the endemic alfalfa mosaic virus (AMV) that was found in most symptomatic plants tested especially in long-established paddocks. More extensive surveys would be required to measure AMV incidence in lucerne seed crops and potential impacts on seed yield and quality.
More information: Dr Ralf Dietzgen, UQ-QAAFI, (07) 3346 6503 firstname.lastname@example.org
The Lucerne Australia AGM was held on the 21st September at the Keith Institute Ruth Wheal Room.
Here is a summary of the presentations by the pre-AGM guest speakers.
Dr. Ainsley Seago , Collection Manager, Insects, Agricultural Scientific Collections Unit , New South Wales Department of Primary Industries, Orange Agricultural Institute
Dr Seago is heading up the Seed Wasp Project which has been funded by RIRDC. She is a skilled insect taxonomist and is highly experienced in conducting scientific literature reviews, extracting, amplifying, and analysing insect DNA and working with growers in primary industries.
She gave a very enlightening talk on the project and gave this outline of what will happen.
The project commenced June 2016
1. Literature review
2. Develop PCR test for LSW
3. Glasshouse studies of behavior and life cycle
Field studies: can soil sampling predict LSW numbers
Literature review strategy:
- All available scientific publications on Bruchophagus roddi (~last 50 years)
- Closely related and/or ecologically similar wasps
- biology and control of other insects with similar seed-infesting lifecycles
She went on to explain that the Lucerne Seed Wasp (LSW) is similar in habit to the Citrus gall wasp (CGW) which is controlled by horticultural mineral oil which deters CGW egg-laying. In the southern citrus regions, three sprays of an oil product 10-14 days apart at 0.5% during CGW emergence provided good control.
• Foliar sprays never, ever work for seed- galling wasps
• Systemic insecticides work for tree gallers but with a crop like lucerne, you would not want these chemicals used.
- Control of “volunteer” plants is very, very important
- Yellow sticky traps are effective for monitoring
What’s next for this project?
- Publish academic and lay summaries of lit review
- Collect more DNA samples across Australian range of LSW
- Design soil sampling approach to examine correlation(s) between soil “bank” of overwintering wasps and subsequent pops
- Rubidium chloride labeling : what percentage of LSW are from the “home team” vs. extra-paddock populations?
Pollinator for Profit Project
Professor Andrew Lowe
Deputy Dean – Partnerships and Collaboration
Faculty of Sciences
University of Adelaide
Professor Lowe said that there had been a global decline in the number of pollinators and of native habitat. There has also been a serious threat to the pollinators with colony decline disorder and varroa mite affecting honey bees. The varroa mite has recently been found in New Zealand and the experts expect that with the next 2-5 years it will be in Australia.
The feral honey bee population provides 70% of pollination for crops so a varroa incursion is a major threat.
This project will look at what the native pollinators are – they are not affected varroa if it comes in – and how to revegetate areas to increase the number and efficacy of native pollinators.
The SA part of the project has received the lion’s share of funding because of high value crops like almonds, pears, canola and lucerne being important to the state.
Golden Dodder – Industry Code of Practice
District Manager, Upper South East at DEWNR, Keith
The project is currently being organised and soon we will be asking from input from growers through case studies conducted by LA EO, Jenny Aitken.
This is collaboration between PIRSA and Biosecurity SA.
This project will develop and implement a national biosecurity code of practice for preventing golden dodder contamination in the Australian lucerne seed industry. Such a code of practice will have two key benefits; it will protect national export markets (through farmers adopting improved detection methods) and it will build the capacity of farmers to conduct on-farm prevention and rapid eradication of golden dodder incursions.
This project seeks to capitalise on gene probe PCR technology developed for the rapid detection of golden dodder contamination of seed lots.
New Seed Wasp Research Project
Lucerne Australia (LA) is delighted to announce that we have been successful in obtaining funding for a seed wasp project, which will be funded through Rural Industries Research and Development Corporation (RIRDC) using levies collected by pasture seed industry growers.
Three organisations –CSIRO, SARDI and NSW DPI – were approached to provide a quotation and method for managing seed wasp over a three-year period, with some guidance by LA.
Following a detailed review of the proposals and face-to-face interviews with RIRDC and LA representatives, NSW DPI has been successful through the process.
A total of $89,300 will be invested in this project from May 2016 to January 2019.
1) The Research
The research has three parts:
a) Literature Review
A comprehensive literature review. This will summarise existing knowledge on the biology of seed wasp, as well as other insect pests that are biologically similar. The resulting report will encapsulate the current body of knowledge of seed-feeding wasps and other insects, their natural enemies, and known methods for control. This review will also yield candidate primer sequences for developing a PCR test for presence/absence of seed wasp DNA.
b) Capture data about behaviour, develop PCR test
Capture data about the emergence timing, flexibility thereof, and regional variation in seed wasp populations. Live wasp adults and larvae from lucerne paddocks in NSW and SA will be collected. Some samples will be used as a source of DNA to develop a PCR test for seed wasp. Live seed wasp will be used to establish viable glasshouse/CT populations. These will determine how seed wasp pupation and emergence time respond to changes in temperature and humidity, and whether these patterns are consistent between populations (e.g. in SA vs. NSW wasps). The research will also determine whether non-lucerne weeds e.g. clover/trefoil, can act as reservoir hosts for seed wasp.
c) Soil sampling to predict numbers
In order to develop an approach to predicting seed wasp populations, soil samples will be collected from growers and several methods of quantifying infested seeds will be trialled. These include light microscopy, PCR testing, and a qPCR, which will identify both seed wasp and its hyperparasites simultaneously. The project will also analyse seed wasp dispersal through rubidium chloride labelling. Analyzing population genetic data of seed wasp in SA and NSW will reveal this species’ dispersal patterns on a larger scale.
2) NSW DPI Project Managers
The primary Project Investigator will be Dr Ainsley Seago. She is a skilled insect taxonomist and is highly experienced in conducting scientific literature reviews, extracting, amplifying, and analysing insect DNA and working with growers in primary industries. Co-Project Investigator will be Professor Gurr, who has led numerous pest management projects in Australia and overseas. He is well known internationally for his work on applied insect ecology and developing ecologically based strategies to combat pests. His chief contribution has been to develop strategies for promoting the activity of natural enemies of pests.
3) Background to the Project
Seed wasp is attracted to flowering lucerne and lays eggs into immature seed in young developing lucerne pods. Therefore, it needs lucerne pods to complete its lifecycle. Financial losses from seed wasp have been accepted over time due to a lack of understanding of the damage it does. But chemicals are not a workable option as its lifecycle is extremely short with continued overlapping generations e.g. all lifecycle stages are present at the same time.
Seed wasp was prevalent in the 1990s in seed growing regions but its presence declined in the 2000’s due to a greater understanding of the importance of sanitary practices, as recommended in RIRDC-funded research done by James De Barro.
However, industry experienced an extreme population of seed wasp in 2012 due to the widespread presence of unmanaged lucerne during the wet summer conditions in the year prior. Acres of lucerne were permitted to set seed and the consequence was a seed wasp population explosion with yield losses in excess of 80 per cent.
Then in 2015, another large population of seed wasp emerged. Losses were high in some regions, but it impacted on the seed processing to an event greater level than in 2012. More seed needed drying to keep it safe. Screens, length separators, chutes and scarifiers blocked up faster than in 2012 and screens needed thorough cleaning.
Many agronomists in south-east SA now recommend growers lock-up paddocks for seed production earlier in an attempt to minimise damage. Although many growers heed that advice they have concerns that it will come at a yield penalty.
4) Next Steps
LA is proud to have lobbied hard for investment in a seed wasp project over the past 18 months as this has been a major industry issue for many growers in recent years.
We will be approaching industry stakeholders – growers, service providers, agronomists and seed cleaners – in coming months, to participate in a major industry workshop in spring 2016. This will include a major presentation by Dr. Ainsley Seago on biology, control, and history of seed wasp, the outcome of the literature review and the approach for steps two and three of this project. There will also be regular progress reports and a final report extensively delivered to industry in early 2019.
We are confident that this project will deliver outcomes to more effectively manage this pest, and potentially lead to better control, and eventual reduction and even eradication of this pest.
Summary: 2016 Annual Trial Site Field Day
Over 65 grower and associate members attended the 2016 Lucerne Australia trial site field day, which was held in the Keith region of South Australia on Wednesday 10th February.
Members travelled by bus to the “Evaluating alternative fertilisers to maximise lucerne seed yield trial” site at Brecon Proprietors. Here, they received the latest results and participated in a crop walk.
On return to Keith, members received marketing updates from PGG Wrightson Seeds, Heritage Seeds, Seed Genetics International and Naracoorte Seeds about the forthcoming season. Seed Services Australia also provided an update on their certification services.
Attendees also heard from a number of associate member machinery dealers who showcased their products and services, including Kuhn, Bogballe, Sulky and Agrex Kylo spreaders. The event concluded with casual drinks and networking.
Final Report: RIRDC-funded Drop-tube Irrigated Lucerne Seed, Herbage Yield and Plant Persistence Trial now available
Lucerne Australia received RIRDC funding to undertake a five-year 'Drop-tube irrigated lucerne seed, herbage yield and plant persistence trial' near Keith, South Australia. This evaluation was important to obtain and compare lucerne herbage and seed yield data using the current best practice system of drop tube irrigation.This research is ultimately targeted for uptake by lucerne seed growers, but other beneficiaries include advisors, agronomists and other service providers.
This research evaluation was conducted over a five-year period. Key findings show the performance of lucerne seed varieties under this system between 2010 and 2015. The major funding for this project has been through the RIRDC pasture seeds program with other funding by Lucerne Australia and industry contributions by seed marketers. This trial has recently been completed and we thank everyone who participated. Click here to view the final report.
Sprayer Set-Up Day Summary
Lucerne Australia held a 'Sprayer Morning’ at Bordertown Football Club on Tuesday, 28 October from 8-11am.
It included special guest speaker Bill Gordon from Lawrence in NSW, who has spent over 20 years working in the area of pesticide application technology area, with the last 12 years as a private consultant focusing on training, extension and research. Bill currently works with industry to discuss application technology and to raise awareness of strategies to improve efficacy and reduce spray drift across Australia.
Following the presentation, the group were showcased a range of self-propelled spraying equipment from Case, Hardi, Goldacres and John Deere, courtesy of local machinery dealers O’Connors, Wickham Flower, Farmers Centre and Wise Farm Equipment.
To be a focal point for the industry and to enhance the Australian lucerne seed industry.