By Carlito Balingbing and Glenn Concepcion
In a significant stride towards safeguarding global food security and reducing reliance on harmful pesticides, a new study has identified simple, environmentally friendly attractants that can effectively monitor and control insect pests in stored rice. This innovative research, spearheaded by scientists from the International Rice Research Institute (IRRI) and partner institutions, offers a sustainable path to protect one of the world’s most vital staple foods.
Every year, insect infestations in suboptimal storage systems can lead to staggering quantitative and qualitative grain losses, sometimes reaching up to 85%. Beyond just weight loss, these pests degrade the quality of rice, reducing its nutritional value, causing foul odors, and even promoting the growth of dangerous fungi and mycotoxins like aflatoxin, posing serious public health risks. With cereal grains comprising 28% of the world’s food supply, protecting them is paramount as the global population continues to grow.
Current methods for controlling these pests often involve extensive insecticide applications, including neonicotinoids and phosphine fumigants. While effective, these chemicals come with severe drawbacks, including environmental contamination, harm to aquatic ecosystems, and the development of pesticide resistance in target insects. The urgent need for safer alternatives has driven researchers to explore natural, chemical-free solutions.
The study, co-authored by Carlito Balingbing, Nurmi Pangesti, and Nguyen Van Hung from IRRI, alongside IRRI consultant Martin Gummert and Oliver Hensel of the University of Kassel, focused on evaluating “makeshift attractants”, readily available and simple technologies to lure and trap key rice pests. The goal was to complement existing acoustic detection devices, which can identify hidden insects, by bringing scattered pests to a central point for easier monitoring and elimination.
The research utilized one-ton capacity storage systems, filled with a mixed variety of rice paddy harvested directly from the Zeigler Experiment Station at IRRI, Philippines. These systems were intentionally infested with three major insect culprits: the lesser grain borer (Rhyzopertha dominica), the rice weevil (Sitophilus oryzae), and the red flour beetle (Tribolium castaneum), with adult insects collected from a rice milling facility and IRRI’s Postharvest laboratory. Four potential attractants were put to the test: a red Light Emitting Diode (LED), an air blower, a vibration module, and virgin coconut oil, all integrated into an improvised pitfall trap. A control trap with no attractant was also included for comparison. The effectiveness was measured by daily insect counts in the traps and by analyzing changes in rice quality over a six-month storage period.
The findings were striking and offer promising pathways for sustainable pest management. The red LED proved highly effective, capturing a significant number of lesser grain borers (R. dominica) and rice weevils (S. oryzae). Specifically, the red LED, measured at a wavelength of 625 ± 10 nm, lured an average of 54 R. dominica and 56 S. oryzae daily, demonstrating its strong appeal to these insects. The air blower also showed significant potential, successfully attracting R. dominica and the red flour beetle (T. castaneum) by creating a slight air movement within the grain mass. This confirms previous observations that forced air ventilation can enhance trapping efficiency for certain beetle species.
However, not all attractants were equally successful. Contrary to some previous laboratory studies, coconut oil and the vibration module did not significantly attract the target insects in this large-scale storage environment. Researchers noted that the much larger storage space in this study, compared to smaller lab setups, might have influenced the insects’ dispersal and response to the lures.
The study also starkly highlighted the destructive impact of unchecked infestations. Over six months, insect populations surged exponentially, with R. dominica increasing by 43 times, S. oryzae by 18.6 times, and T. castaneum by a staggering 186 times. This population boom directly correlated with a significant decline in rice quality: milling recovery decreased by 2.9%, head rice yield plummeted by 10.1%, and the percentage of broken rice soared by 27.3%. These losses directly reduce the amount of marketable rice and farmers’ income.
This research, supported by funding from the Academy for International Agricultural Research (ACINAR) through ATSAF Academy and with crucial financial and equipment support from IRRI, validates the use of low-power red LEDs and simple air blowers as effective, chemical-free tools for pest management. These sustainable attractants, which pose no risk to human health or the environment, can be integrated with advanced detection systems, like acoustic sensors developed complementing this research, to offer enhanced pest monitoring and control in rice storage.
Looking ahead, the team suggests optimizing the design of these pitfall traps and attractant specifications to further boost their efficiency. Future work will also involve evaluating these attractants in real-world farmer storage facilities and commercial warehouses, where infestations are most prevalent. Testing other effective LED wavelengths beyond red could also lead to even more efficient solutions.
By providing scientifically rigorous yet practical solutions to a pervasive agricultural challenge, this study points the way to more simple and sustainable rice storage management, helping ensure food security and benefiting farmers, consumers, and the environment alike.
Read the full study here:
Insect attractants for enhanced monitoring and control of pests in rice storage
Carlito Balingbing, Martin Gummert, Nurmi Pangesti, Nguyen Van Hung, Oliver Hensel
Journal of Stored Products Research, Volume 113, June 2025
https://doi.org/10.1016/j.jspr.2025.102697
Related presentation:
Effective control of insect pests’ population in stored rice using LED attractants
Carlito Balingbing, Nguyen Van Hung, Sascha Kirchner, Oliver Hensel
International Conference on Research on Food Security, Natural Resource Management and Rural Development, Tropentag 2024, 11-13 September 2024, Vienna, Austria, Poster Presentation
