Scientists Find Rice Spikelets Trap and Kill Fall Armyworm Larvae
Scientists have discovered a surprising trait in rice plants that may change pest control practices. Researchers from the Arkansas Agricultural Experiment Station found that rice plants can trap and kill fall armyworm caterpillars, a major crop pest.
The research was led by Devi Balakrishnan and supervised by Rupesh Kariyat from the University of Arkansas. The team observed that young caterpillars were getting trapped inside rice spikelets, the part of the plant where grains developed. Their findings were published in the journal Ecological Processes.
“This was not in the plan,” said Balakrishnan, Ph.D., in the department of entomology and plant pathology for the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas Division of Agriculture. “I was doing another experiment on rice with fall armyworms and started noticing these caterpillars were inside the spikelet, and they were dead.”
Rice plants release a faint floral scent during flowering, which attracts caterpillars. As the caterpillars move toward the floret to feed, they get stuck on small hair-like structures called trichomes. When the spikelet closes, the trapped caterpillars cannot escape and die inside.
In experiments, about half of the young caterpillars became trapped and died within two days. The researchers also found that caterpillars were more attracted to flowering spikelets compared to later growth stages.
This discovery highlights a natural defense system in rice plants. The study suggests that trichomes and flower scents work together to protect the plant from pests feeding its reproductive parts.
Researchers believe this finding could lead to new pest management strategies. By increasing or mimicking the floral scent, it may be possible to attract more pests into natural traps, reducing the need for chemical insecticides.
“The running joke in our lab is that no matter what you’re studying — even protein kinases — at some point you’ll be counting trichomes,” said Rupesh Kariyat, an associate professor of crop entomology, served as Devi Balakrishnan's adviser for the study. “This just reminded us that sometimes the most interesting science starts when something doesn’t go according to plan.”
Fall armyworm is a growing global concern as it develops resistance to many pesticides. Since rice is a staple food for billions of people, this natural defense could play an important role in protecting crop yields.
The discovery also shows how unexpected observations can lead to important scientific breakthroughs and new ideas for sustainable agriculture.
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