Overview
Background
Dr. Jhoana Opena, a seasoned researcher, joined The University of Queensland as a Postdoctoral Research Fellow in 2021. Dr. Opena has over 18 years of experience in research related to Integrated Pest Management (IPM) in vegetables and weed management within rice-based cropping systems across Australia, the Philippines, Cambodia, and Lao PDR. Previously, she worked as an Associate Scientist in the Weed Science group at the International Rice Research Institute and was appointed as an Adjunct Associate Professor at the University of the Philippines in Los Baños. She successfully completed her Doctor of Philosophy in Agriculture at Charles Sturt University in Wagga Wagga, Australia, in 2021. Currently, she is working on an ACIAR project entitled “Weed Management Techniques for Mechanized and Broadcast Lowland Crop Production Systems in Cambodia and Lao PDR.”
Availability
- Dr Jhoana Opena is:
- Available for supervision
Qualifications
- Bachelor, University of the Philippines Los Baños
- Masters (Coursework), University of the Philippines
- Doctor of Philosophy, Charles Sturt University
Research interests
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Weed management in rice and rice-based cropping systems
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Weed ecology
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Integrated weed management in direct seeded rice systems
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Weed population dynamics
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Allelopathy and its application for weed management
Research impacts
Through a five-year ACIAR program in Laos and Cambodia, our research co-designed and field-tested integrated weed management (IWM) for mechanised direct-seeded rice, working with partners across 14 villages. The packages (good seed, precise seeding, early water management, mechanical tools, mungbean intercropping, and judicious herbicides) reduced weed-seed contamination by ~90% (≈290 → ~30 seeds/kg) without reducing head-rice yield, improving grain quality and farm returns. Addressing baseline reliance on herbicides (≈43% of farmers in Laos; ~80% in Cambodia), we shifted practice toward safer, targeted use—including drone applications—while training 49 Master Trainers and delivering gender-responsive farmer training that increased women’s confidence in weed ID and safe handling. The work also informed draft national drone guidelines (Cambodia) and herbicide-use guidance (Laos), providing a scalable, gender-inclusive pathway to higher profitability, reduced chemical dependence, and more sustainable rice systems.
Works
Search Professor Jhoana Opena’s works on UQ eSpace
2025
Conference Publication
Efficacy of pre- and post-emergence herbicides in direct-seeded rice in Lao PDR
Lovanxay, Douangsavanh, Xangsayasane, Phetmanyseng, Opena, Jhoana, Lemerle, Deirdre and Mitchell, Jaquie (2025). Efficacy of pre- and post-emergence herbicides in direct-seeded rice in Lao PDR. TropAg 2025 Conference, Brisbane, QLD, Australia, 11-13 November 2025.
2025
Conference Publication
Impact of integrated weed management on grain quality in direct-seeded rice in Lao PDR
Vongxayya, Khamtay, Opena, Jhoana, Xangsayasane, Phetmanyseng, Lemerle, Deirdre and Mitchell, Jaquie (2025). Impact of integrated weed management on grain quality in direct-seeded rice in Lao PDR. TropAg 2025 Conference, Brisbane, QLD, Australia, 11-13 November 2025.
2025
Conference Publication
Mungbean intercropping as a sustainable weed management strategy for direct seeded rice system in Lao PDR
Manivong, Phatsalakone, Opena, Jhoana, Xangsayasane, Phetmanyseng, Lemerle, Deirdre and Mitchell, Jaquie (2025). Mungbean intercropping as a sustainable weed management strategy for direct seeded rice system in Lao PDR. TropAg Conference 2025, Brisbane, QLD, Australia, 11-13 November 2025.
2025
Conference Publication
Farmers perceptions on the use of mungbean intercropping as alternative for sustainable weed management in direct seeded rice systems in Lao PDR
Bouahom, Bounthanom, Palaniappan, Gomathy, Opena, Jhoana and Mitchell, Jaquie (2025). Farmers perceptions on the use of mungbean intercropping as alternative for sustainable weed management in direct seeded rice systems in Lao PDR. TropAg 2025 Conference, Brisbane, QLD, Australia, 11 - 13 November 2025.
2025
Conference Publication
Breeding rice for climate resilience in Lao PDR
Homsengchanh, Laeh, Opena, Jhoana, Mitchell, Jaquie, Lemerle, Deirdre and Xangsayasane, Phetmanyseng (2025). Breeding rice for climate resilience in Lao PDR. TropAg 2025 Conference, Brisbane, QLD, Australia, 11 - 13 November 2025.
2025
Conference Publication
Sustainable weed management in mechanised direct seeded rice system: a 5-year Laos & Cambodia ACIAR project
Opena, Jhoana, Palaniappan, Gomathy, Banayo, Nino Paul Meynard, Sukmawijaya, Adhera, Bouahom, Bounthanom, Chea, Sareth, Manivong, Phatsalakone, Lovanxay, Douangsavanh, Vongxayya, Khamtay, Bunna, Som, Sinath, Pao, Xangsayasane, Phetmanyseng, Sathya, Khay, Abdul Aziz, Ammar, Vial, Leigh, Lemerle, Deirdre and Mitchell, Jaquie (2025). Sustainable weed management in mechanised direct seeded rice system: a 5-year Laos & Cambodia ACIAR project. TropAg 2025 Conference, Brisbane, QLD Australia, 11-13 November 2025.
2025
Conference Publication
Integrating agronomic tools for effective weed management and enhanced rice productivity in Cambodia
Lim, Vanndy, Touch, Veasna, Srom, Sodany, Phoeun, Chetra, Sun, Chanketya, Opena, Jhoana and Mitchell, Jaquie (2025). Integrating agronomic tools for effective weed management and enhanced rice productivity in Cambodia. TropAg 2025 Conference, Brisbane, QLD, Australia, 11 - 13 November 2025.
2025
Conference Publication
Enhancing weed competitiveness in direct-seeded rice for sustainable weed management in Cambodia
Thanak,Tho, Chourn, Orn, Opena, Jhoana and Mitchell, Jaquie (2025). Enhancing weed competitiveness in direct-seeded rice for sustainable weed management in Cambodia. TropAg 2025 Conference, Brisbane, QLD Australia, 11-13 November 2025.
2025
Conference Publication
Development and validation of a QuEChERS-LCMS/MS method for the determination of triazole pesticide residues in rice grains
Bunquin, Michelle Anne B., Daygon, Venea Dara, Opena, Jhoana and Mitchell, Jaquie (2025). Development and validation of a QuEChERS-LCMS/MS method for the determination of triazole pesticide residues in rice grains. Tropical Agriculture (TropAg) 2025, Bowen Hills, QLD Australia, 11-13 November 2025.
2025
Conference Publication
A pilot study on integrating traditional method and enzyme-based biosensor for predictive detection of triazole fungicide residues in rice
Bunquin, Michelle Anne B., Opena, Jhoana, Daygon, Venea Dara and Mitchell, Jaquie (2025). A pilot study on integrating traditional method and enzyme-based biosensor for predictive detection of triazole fungicide residues in rice. UQ-ARSA NextGen Ag Symposium 2025, St Lucia, QLD Australia, 7 November 2025.
2025
Conference Publication
Tasting and testing: identifying high-quality weed competitive genotypes across diverse Lao environments
Vongxayya, Khamtay, Opena, Jhoana, Xaiyatham, Nouy, Homsengchanh, Laeh, Xangsayasane, Phetmanyseng and Mitchell, Jaquie (2025). Tasting and testing: identifying high-quality weed competitive genotypes across diverse Lao environments. 75th Australasian Grain Science Conference, Brisbane, QLD Australia, 20-22 August 2025.
2025
Conference Publication
Translating systematic insights into application: validating conventional method to support emerging technologies for detecting triazole pesticide residues
Bunquin, Michelle Anne B., Daygon, Venea Dara, Opena, Jhoana and Mitchell, Jaquie (2025). Translating systematic insights into application: validating conventional method to support emerging technologies for detecting triazole pesticide residues. 75th Australasian Grain Science Conference, Brisbane, QLD, Australia, 20-22 August 2025.
2025
Journal Article
Exploring alternative detection methods for azole-containing pesticide residue detection in food: a systematic review and future perspective
Bunquin, Michelle Anne B., Daygon, Venea Dara, Opena, Jhoana and Mitchell, Jaquie (2025). Exploring alternative detection methods for azole-containing pesticide residue detection in food: a systematic review and future perspective. Trends in Food Science and Technology, 161 105064, 105064-161. doi: 10.1016/j.tifs.2025.105064
2025
Journal Article
Integrated weed seed impact mills for Southeast Asian Rice systems: could they aid sustainable weed management?
Vial, Leigh, Opeña, Jhoana and Mitchell, Jaquie (2025). Integrated weed seed impact mills for Southeast Asian Rice systems: could they aid sustainable weed management?. Agronomy, 15 (6) 1333, 1-15. doi: 10.3390/agronomy15061333
2024
Other Outputs
Mutual benefits of partnerships between SE Asia and Australia for sustainable weed management
Lemerle, Deirdre, Mitchell, Jaquie, Molesworth, Anika, Opena, Jhoana, Palaniappan, Gomathy, Reade, Cathy and Wunderlich, Nicola (2024). Mutual benefits of partnerships between SE Asia and Australia for sustainable weed management.
2024
Conference Publication
Phenotypic traits associated with weed competitiveness for aerobic rice production system in Australia
Opena, Jhoana, Eam, Sreynich, Vinarao, Ricky, Gong, Wenliu and Mitchell, Jaquie (2024). Phenotypic traits associated with weed competitiveness for aerobic rice production system in Australia. International Temperate Rice Conference 2024, New Orleans, LA United States, 5-8 June 2024.
2024
Conference Publication
Screening weed suppressive rice germplasm in Cambodia and Lao PDR
Opena, Jhoana, Homsengchanh, Laeh, Thanak, Tho, Orn, Chourn, Xangsayasane, Phetmanyseng and Mitchell, Jaquie (2024). Screening weed suppressive rice germplasm in Cambodia and Lao PDR. 23rd Australasian Weeds Conference, Brisbane, QLD Australia, 25-29 August 2024.
2024
Conference Publication
Capabilities of hyperspectral spectroradiometer for differentiating rice and rice mimicry weeds on leaf-level measurement
Sukmawijaya, Adhera, Opena, Jhoana, Akber, Ali, Mitchell, Jaquie and Abdul Aziz, Ammar (2024). Capabilities of hyperspectral spectroradiometer for differentiating rice and rice mimicry weeds on leaf-level measurement. 23rd Australasian Weeds Conference, Brisbane, QLD Australia, 25-29 August 2024.
2023
Conference Publication
Herbicides in lowland rice farming: What's driving the farmer's choice in Lao PDR?
Bouahom, Bounthanom, Palaniappan, Gomathy, Opena, Jhoana and Mitchell, Jaquie (2023). Herbicides in lowland rice farming: What's driving the farmer's choice in Lao PDR?. 28th Asian Pacific Weed Science Society Conference (APWSS 2023), Phuket, Thailand, 26-29 November 2023. Weed Science Solutions for Global Food Security:
2023
Conference Publication
Empowering rice farmers in Laos through gender-inclusive integrated weed management training
Bounthanom, Bouahom, Gomathy, Palaniappan, Jhoana, Opena and Jaquie, Mitchell (2023). Empowering rice farmers in Laos through gender-inclusive integrated weed management training. International Rice Congress 2023, Manila, Philippines, 16-19 October 2023. doi: 10.5281/zenodo.10398315
Supervision
Availability
- Dr Jhoana Opena is:
- Available for supervision
Looking for a supervisor? Read our advice on how to choose a supervisor.
Available projects
Supervision history
Current supervision
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Doctor Philosophy
Impact of pesticide residues on food safety and soil quality in direct seeded rice systems
Associate Advisor
Other advisors: Dr Dara Daygon, Associate Professor Jaquie Mitchell
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Doctor Philosophy
GIS and remote sensing for improved weed management in direct seeded rice
Associate Advisor
Other advisors: Associate Professor Jaquie Mitchell, Professor Ammar Abdul Aziz, Dr Md. Ali Akber
Media
Enquiries
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