session 4: research impact – an end-user’s perspective: phosphine resistance
TRANSCRIPT
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Research impact – an end-user perspective: Phosphine Resistance
Phillip Clamp, Quality Assurance Manager – GrainCorp
Manoj Nayak, Principal Research Scientist – DAF, Queensland
Plant Biosecurity Cooperative Research Centre
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Grains industry has supported stored product protection research for over 3 decades major (historic) research outcomes;- Bunker fumigations, Inert (N2, CO2), sealed storage (BHC, farm), Siroflo, COS, EF
10 year relationship NPBCRC (2007) to present PBCRC, PBCRC;- PBCRC highly engaged with grains, great end-user focus, grains strategy- Focus on delivery of end-user tools for maximum impact- PBCRC is best option for stored product protection research;
Excellent $ multiplier, collaboration Phosphine research is often foundation for other grains post harvest research Useful range of tools to potential game changer in Amorphous silica (grain/structural)
Research and Grains a successful partnership
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Australia has a unique set of grain protection circumstances:- Legislated nil insect detection policy for exports- Domestic trading contracts also specify nil insects
We harvest and store grain in tropical/sub-tropical climates:- This creates perfect conditions for proliferation of insects
Deregulation has placed pressure on insect control:- New (less informed) entrants, use of alternate supply chains, alternate cargo
assembly methods, just in time delivery, more insect remedy at ports- Competition and reducing costs challenge hygiene and other quality controls
Our operating environment
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Phosphine- Is used world-wide as a grain fumigant- Phosphine is cheap, versatile and “residue-free”- We over rely on Phosphine as a grain fumigant on farm and in industry- We regularly select for resistance (cost, infrastructure, leaky enclosures)- Phosphine has been a “silver bullet” sustaining export and domestic markets- Other chemistries/controls expensive or market limiting (residues)- Phosphine resistance is real and growing- Rusty grain beetle not controlled by most current rates- We must keep Phosphine useful for the long haul
Managing Phosphine resistance is Grains’ greatest challenge
Phosphine
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CRC and Grains took a strategic direction to sustain Phosphine in Australia, supported (at least in part) by the following research examples:- Resistance monitoring, distribution and systems approaches:
CRC3035, CRC3036, CRC3040, CRC3150- Phosphine resistance management strategy CRC3036- Alternatives to Phosphine: CRC3038, CRC3099- Revised Phosphine treatment protocols: CRC3150- Sulfuryl fluoride:
Fumigation protocols CRC3036, Residues CRC3037
PBCRC and Phosphine resistance, some examples:
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GrainCorp have adopted the following Phosphine resistance management tools from the CRC toolbox:- Monitor, manage and test suspect resistant insects:
Know and manage your enemy- Phosphine resistance management strategy:
Routinely use alternate chemistry (protectants and SF) as PH3 resistance breaker Focus on hygiene, monitoring of systems such as sealing, inspection, audit and report
- Revised Phosphine and SF treatment protocols: Allows for precision treatment (CxT) relevant to situation
- Precision application allows for greater insect mortality and flexibility: Varying C and T can; lower costs, supports resistance management, meet cargo timelines
What is GrainCorp’s end-user adoption?
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Others that have adopted Phosphine resistance management tools from the CRC toolbox include:- Other bulk handlers (Viterra, CBH, Grainflow, Emerald)- Smaller private storers- Growers- GRDC via publications/extension specialists- Researchers nationally and internationally- Chemical companies, registrants
Who else will use will use this?
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Theme 1: Tools, technologies and strategies to safeguard international markets for grain and horticultural exports
Theme 2: Better management of established pests Not all research outputs bring direct value to GrainCorp, however; Above themes well supported; strategic and end-user outcomes met Many of the research outputs (or work in progress), particularly work in
Phosphine and Phosphine alternatives are, this:- Sustains our pest management efforts- Extends the life of Phosphine- Allows us to meet domestic and export market requirements
All of the above safeguards and sustains Australian Trade
Program 3 – Safeguarding Trade - Summary
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For more information, please email: [email protected]
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Science behind phosphine resistance Two major genes (rph 1 and rph 2)
- Weak resistance - R1R1 (5-15 X)- Strong resistance - R1R1 + R2R2 (>400 X)
Synergistic effect Multiple variants – a common molecular platform needed
Example - to control all life stages- at 720 ppm (1 mg/L)
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Impact of phosphine resistance Direct Cost:
Multiple treatments, alternatives Demurrage Rejection and treatment at destination
Reduced quality and integrity Jeopardises food security/market access, loss of reputation
‘Nil tolerance’ Research costs
Multi-millon dollar investment globally
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Timely detection and accurate diagnosis Characterisation of resistant phenotypes Understanding of molecular genetics – Rph1 & Rph2 - Platform Understanding of ecology and population genetics (movement
and colonization) An integrated approach
- Develop alternatives- Modify protocols (conc. x time)- Utilise molecular and ecological knowledge
Approach to keep phosphine viable
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Strong resistance problems over the years Rhyzopertha dominica (Lesser grain borer) Sitophilus oryzae (Rice weevil) Tribolium castaneum (Red flour beetle) Oryzaephilus surinamensis (Saw-toothed grain beetle) Cryptolestes ferrugineus (Rusty grain beetle) Liposcelis bostrychophila (Psocids) C. ferrugineus
- Strongest ever reported (1300x)
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Current problem - Rusty grain beetle (C. ferrugineus)
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Problem being addressed – Strongly resistant RGB
Time to population extinction at 720 ppm at 25°C
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Monitoring continues…..(bioassay and mol. methods) Developing Sulfuryl fluoride (SF) as ‘resistance breaker’ Developing higher rates - cylinderised phosphine – label change Evaluating current standards for Aluminium phosphide (sealing,
recirculation, large silos) – label change Validating new protocols - industry-scale field trials Determining ‘time to reinfestation’ after fumigation ‘Decision Making’ tool integrating all available knowledge and methods
Overview of current Phosphine Resistance Management
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Results so far – new sulfuryl fluoride protocols
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Results so far – a comparative assessment of SF protocols
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Results so far – field validation of SF protocolTarget CT: 400 mg-h/L (1.7 mg/L for 10 days)
1500 tonne sorghum in 2300m3 siloMixed-age resistant pests in cages
Temperature:Top : (avg: 22.5°C)Bottom : (avg: 27.3°C)
Results:Complete control of six strongly phosphine resistant pest species RGB, LGB, RFB, RW, SGB, Psocids
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Results so far – ‘Time to reinfestation’Large bunkers - sorghum/wheatPre and post fumigation sampling for natural infestations23 samples at two depths
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Results so far – No cross resistance to phosphine-RRGB, C. ferrugineus
0.1 1 10 100Lethal Time (hours)
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0.1 1 10 100Lethal Time (hours)
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Results so far – Impact of SF on Str. Rusty grain beetles
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Excellent candidate as an alternative to phosphine – no cross resistance
Time and temperature have significant effect on effectiveness
Time more critical than concentration
At 4 days - registered rate (1500 CT) at 25°C fails - RFB and RW
Half the concentration of SF required at 30°C than 25°C
Minimum 7 days exposure period – for all four pest species
‘Time to reinfestation’ - 3 months after a successful fumigation No survivors from the original infestation
Re-infestation (invasion) did not occur
Fumiguide needs significant changes – bunker fumigation
Strategic use to break ‘phosphine resistance cycle’
Results so far – Key points on SF
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Results so far – new phosphine protocols for RGB
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Results so far – proposed changes to cylinderised phosphine label
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Results so far – field validation of phosphine protocol
Target CT: 1080 ppm for 12 days)
1600 tonne sorghum in 2300m3 siloMixed-age resistant pests in cages
Temperature:Top : (avg: 22.3°C)Bottom : (avg: 25.5°C)
Results:Complete control of six strongly phosphine resistant pest species RGB, LGB, RFB, RW, SGB, Psocids
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Results so far – Aluminium phosphide label Aim: Do large farm silos need recirculation?
Passive Recirculation
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Results so far – on farm trial of Aluminium phosphide• Flat bottom 1400 tonne silos
(Kotzur) at Weemelah• Wheat with 12% m.c.• 1.5 g of phosphine m3
• Temp.: 27-31°C• Gas monitored 3 times daily
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Current pressure half-life standard of 5 minutes - suitable for large silos
Recirculation has significant impact- doubles the amount of phosphine available to kill pests
Resistant RGB can be controlled on farms in large silos Exposure period extended past 30 days with passive fumigation Reduced exposure period to 14 days by using recirculation
Results so far – Aluminium phosphide use
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Recognised world leader- Only country systematically monitoring and managing resistance – proper
characterisation - Frequency of resistance remains below 10% compared to more than 80-90% in overseas - Unique resistance database – AGIRD (>30 years)- Unique collection of laboratory populations - International invitations (Editorial Board in journals, key notes, workshops, training)- Invited book chapters, publications
Other countries look to us for leadership- KSU is partnering with PBCRC- India $3M Grand Challenge project/$1M AISRF Project - Brazil, China, Indonesia, Thailand, The Philippines, Vietnam, Turkey
Where are we now?
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Discovery of genes responsible for phosphine resistance – Science Development of Molecular Diagnostics – Heredity Comparative genetic analysis (global) – PLOS One, Heredity Psocids: resistance and management – Annual Review of Entomology Characterisation of strong resistance – Pest Management Science, Pesticide
Biochemistry and Physiology Development of ‘Quick tests’ to diagnose strong resistance - Pest Management Science New phosphine protocols, cross-resistance studies – Pest Management Science Comprehensive studies on inheritance, fitness & prevalence – Journal of Stored
Products Research Analysis of resistance monitoring database (AGIRD) – Environmental Ecological
Statistics, Journal of Stored Products Research
Major Breakthroughs
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National Resistance Management Strategy - network of pest and resistance managers, researchers- needs major changes to include new information (last updated in 2009)
ecological knowledge, SF, on farm storage, protectants
GRDC National Extension Network National Working Party on Grain Protection Industry Workshops/Field Days Scientific and extension publications
- Peer-reviewed journal papers- GRDC Publications (eg. Growers Update, Ground Cover)
The Delivery Plan
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Close industry-researcher collaboration Industry has flexibility to use treatments Decision making - treatments and storage performance Strategic direction on performance of resistance management Residue and environmental issues need to be addressed Information to biosecurity officers and extension networks Timely containment/control of resistant populations Enhanced knowledge
incidences and selection for resistance to phosphine utility of SF as a new tool
Summary - The Industry Impact
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Phosphine and Sulfuryl fluoride co-treatment Additive increase in toxicity Effective against PH3-resistant insects in key pest species Adults and eggs controlled by ½ PH3 + ½ SF – 7 days Well below the current label rates of both fumigants
- Lower residue level and environmental risk- Shorten PH3 fumigation period- Reduced selection pressure on both
Major modifications to Fumiguide for SF use (Douglas Products) Molecular diagnostics
A platform to diagnose strong resistant mutants of all key species- Resistance gene frequency - Evaluation of management strategies
Resistance monitoring for SF Studies on desorption
The Future….
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Research Team (PBCRC3035, 3036, 3150, 3160, 3114)- DAFQ - Manoj Nayak and Team (Greg, Pat, Andrew, Raj, Raman, Philip, Hervoika)- UQ- Paul Ebert and Team- NSWDPI - Jo Holloway and Team- DAFWA - Rob Emery and Team- GrainCorp - Robin Reid and team- CBH - Ern Kostas and team- Viterra - Greg Hopkins and team- CYTEC – Justin Tumambing
Acknowledgements
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For more information, please email: [email protected]