Cicadas are a noisy, natural part of summer as brood after brood emerges, singing loud and proud, before mating and laying hundreds of eggs.

They are harmless to humans, but can damage trees. "Cicadas are harmful for willows, cherry trees and sweet osmanthus trees," said Ruan Wangzhou, chief of the Hangzhou Greening Management Station, which is in charge of the gardens and greenery throughout Zhejiang's provincial capital.

Take cherry trees, for example. Each July and August, the juice in their buds tends to make them the favorite food and egg-laying places for cicadas. The insects slash the buds to lay their eggs, which can cause the trees to wither.

To tackle the problem and raise public awareness about the pests, the station recently invited residents to catch cicadas in a park in Hangzhou.

The campaign was well received and over 50 people showed up, far exceeding the 20 expected. The station also invited Jin Sucui, a 62-year-old expert from Lishui, Zhejiang, to teach them how to catch the cicadas.

Cicadas are a traditional delicacy in Lishui, and Jin has been catching them since she was a young girl.

"Catching them is actually quite simple," she said. "All you need is a slender rod, a piece of sticky paper and a bag to hold the cicadas. Just keep your hands steady and your eyes on the sticky paper. Remember, their wings are the most vulnerable part."

Jin caught hundreds of cicadas in two hours, a performance few others in the park could match. In Lishui, from June to August, protein-rich cicadas are not regarded as pests, but are braised in soy sauce or fried, making them a seasonal delicacy, Jin said.

Ruan said he hopes more people will take part in the campaign and protect the city's greenery.

"Parents can bring their children along to catch cicadas during summer as a way to get in touch with Mother Nature, and enhance their awareness of protecting greenery and the environment," he said.

Xu Ting contributed to this story.