China expands insect radar network for early crop pest warnings

China is expanding a network of insect-tracking radars designed to detect migratory crop pests before they reach farmland, giving farmers more time to protect major grain crops.

In east China's Zhejiang Province, an important migration corridor between northern and southern rice-growing regions, one radar station operates beside a paddy field.

The system can detect tiny insects passing through the air and collect data including their size and weight.

Among the pests being tracked is the rice planthopper, a migratory insect that weighs about 1 milligram and stretches only a few millimeters long.

It damages rice plants by piercing their stems and sucking out sap.

During a demonstration, technicians used a drone to carry a single rice planthopper about 300 meters from the radar.

Moments later, the system displayed measurements of the insect's length, width and weight.

Despite their small size, migratory pests can cause extensive crop losses.

Of the 11 pests classified as first-class agricultural pests in China, eight can ride seasonal winds and travel more than 100 kilometers overnight.

Between 2021 and 2024, those eight pests affected an average of 83 million hectares of grain fields annually, accounting for 40% of pest-related damage to China'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 more than 1,000 offspring, allowing infestations to grow rapidly.

The risk has been particularly evident this summer.

Outer winds from recent typhoons have accelerated pest migration into parts of eastern China, while high humidity has created favorable conditions for rice planthoppers to reproduce.

In central China's Hubei Province, rice grower Sheng Yunxiong said planthopper numbers surged suddenly in August.