A cover-all monitoring and testing network has been established to ensure all the cowpeas shipped to the inland from south China's island province of Hainan are safe, a senior agricultural official said Wednesday after a pesticide scandal triggered worries.

All the cowpea wholesalers are now put under the monitoring network to ensure no unchecked or tainted cowpeas are sold to the inland, said Vice Agriculture Minister Wei Chao'an.

The government's measures to improve food safety have taken effects, Wei said at a press conference on the sidelines of the annual session of the National People's Congress, the country's top legislature.

Both sales and prices of cowpeas have seen remarkable rebounds from previous lows, he said.

The average purchase price of cowpeas climbed to 2.6 yuan (38 U.S. cents) per kilogram on Sunday, almost two weeks after it dropped to the lowest level at 0.4 yuan when the scandal caused widespread safety scare.

The government enhanced market inspections on both cowpeas and pesticide after the scandal and banned sales of cowpeas without quality certification, Wei said.

Some 280 kg of prohibited pesticide were found after the examination of 1,732 pesticide stores on the island, he said.

Last month, authorities in Wuhan, capital of central China's Hubei Province, found about 3.5 tonnes of cowpeas from Hainan were treated with isocarbophos, a pesticide whose use is banned on fruits and vegetables.

Several provinces in southern and eastern China later reported more findings of the tainted cowpeas in their markets, leading to a crisis in confidence on the agricultural products grown on the tropical island.

There have been no reports that people were sickened by the contaminated cowpeas.

Hainan is a major supplier of fruits and vegetables to the inland regions in winter.