Insect-tracking radars to bolster crop protection
In East China's Zhejiang province, a key migration corridor where northern and southern rice-growing regions converge, a radar station operates at the edge of a paddy field. When a small pest flies past, the system can capture its size, weight and other identifying data.
One target is the rice planthopper, a migratory insect weighing just 1 milligram and measuring a few millimeters long. It pierces rice stalks and sucks out sap.
During a demonstration test, technicians flew a drone carrying only one rice planthopper about 300 meters from the radar. Moments later, a monitoring screen displayed the pest's body length, width and weight. A network of these critical platforms is now being expanded across China to help farmers battle migratory pests that threaten the country's food supply.
Liu Dazhong, an associate researcher at Zhejiang-based Xianghu Laboratory, which monitors major migratory pests, said milligram-level measurements can now be achieved with precision.
"It has placed us at the forefront globally," Liu said.
This tiny pest can pose a substantial threat. Of the 11 pests on China's list of first-class agricultural pests, eight can ride seasonal winds and travel more than 100 kilometers overnight across regions. Between 2021 and 2024, these eight pests infested an average of 83 million hectares of grain fields annually, accounting for 40 percent of all pest-related damage to the country's rice, wheat and corn, according to the National Agro-Tech Extension and Service Center.
Wu Kongming, an academician at the Chinese Academy of Engineering, said a single adult migratory pest can produce over 1,000 offspring.
In August, peripheral winds from recent typhoons accelerated pest migration into the region, while high field humidity created favorable conditions for rapid planthopper breeding.
The pressure on pest and disease control has, as a result, increased greatly in this area recently. Scientists warn that once pest numbers get too high, rice plants turn yellow and fall over.
In severe cases, it may lead to total crop failure.
Rice grower Sheng Yunxiong, based in Central China's Hubei province, said he had rarely seen so many planthoppers in previous years, but their numbers surged suddenly in August. "I followed the guidance from agricultural technicians and applied pesticide in time. The infestation is now under control," he said. He added that many farmers used to mistakenly believe that rice near maturity did not need pest protection.
Chinese research teams have developed multiple types of insect radars that now provide real-time data on where pests originate, their numbers and their trajectory. The system moves the warning window from "detection after arrival" to "alert before landing", giving farmers 24 to 48 hours of advance notice, a critical period for coordinated control efforts.
Across the country, 65 insect radars are now connected to a national monitoring platform. By 2030, the network is expected to exceed 150 radars, covering all primary migration corridors and eliminating blind spots in core farming areas.
It will form a three-tier defense: radar-based high-altitude monitoring, aerial interception of adult insects and precise ground trapping.
Moreover, migratory pests are a global problem. For example, the fall armyworm, a pest native to the tropical and subtropical regions of the Americas, has devastated maize and other staple crops across Africa since its arrival in 2016. In January 2019, the fall armyworm migrated from Myanmar into Southwest China's Yunnan province, and quickly spread to 18 provincial-level regions. Such threats make international cooperation essential.
China has, notably, shared its tech expertise in cross-border migratory pest control with other Asian countries including Laos, Vietnam and Kazakhstan, via the United Nations Food and Agriculture Organization's South-South cooperation programs.
XINHUA
