KUNMING, Aug. 4 (Xinhua) -- Locust swarms invaded an area of 10,389 hectares in southwest China's Yunnan Province as of Sunday, local authorities said Tuesday.

A total of nine county-level regions in four prefectures and cities were affected, including the city of Pu'er and Xishuangbanna Dai Autonomous Prefecture, according to the office that leads the work to curb the insects in the province.

The upsurge was caused by the second migration of the locust swarms as the weather clears and the temperature is suitable.

Local authorities have used chemical and biological means including spraying pesticides by drones to curb their spread on about 34,640 hectares since the locusts were first found on June 28. Over 80,000 people have also been mobilized.

Experts said the population of locusts entering China has gradually lessened, but the stock is still large and the distribution wide. Enditem