China builds pest radar network to protect grain crops

BEIJING, Aug. 31 (Xinhua) -- A network of insect-tracking radars is being expanded across China to help farmers battle migratory pests that threaten the country's food supply.

In east China's Zhejiang Province, a key migration corridor where northern and southern rice-growing regions meet, 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 plant hopper, 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 plant hopper about 300 meters from the radar. Moments later, a monitoring screen displayed the pest's body length, width and weight. Such milligram-level measurements can now be achieved with precision, said Liu Dazhong, an associate researcher at Zhejiang-based Xianghu Laboratory, which monitors major migratory pests. "It has placed us at the forefront globally," Liu noted.

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 km overnight across regions. From 2021 to 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. "The offspring of one adult pest can reduce yields by one-third or even more," he noted.

Outer winds from recent typhoons have accelerated pest migration into the region this month, while high field humidity has created favorable conditions for rapid plant hopper 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 will 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 plant hoppers in previous years, but their numbers surged suddenly this 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.