In this photo taken Friday May 13, 2011, a farmer holds up the packaging for chemicals used on watermelons that had burst in Danyang city in eastern China's Jiangsu province. (AP photo)

Chinese farmers in eastern China have been left stunned after their watermelons began to explode one by one.

Initial media reports found farms in Jiangsu province were losing acres of fruit because of the problem.

Reports indicated, the overuse of a chemical that helps fruit grow faster was blamed in one report by China Central Television.

But agriculture experts were unable to explain why chemical-free melons were exploding, BBC reports. They cited the weather and abnormal size of the melon as factors.

China Central Television said farmers were overspraying their crops with the growth promoter, hoping they could get their fruit to market ahead of the peak season and increase their profits.

According to the Xinhua news agency, 20 farmers in a village in Jiangsu province planted imported seeds from Japan, with 10 households saying their watermelons began exploding last month.

Farmer Liu Mingsuo told Xinhua that more than two-thirds of his crop had blown up.

He said he had used chemicals to boost their growth on 6 May, and the following day more than 180 melons exploded. Mr Liu was reported to be the only farmer from the 10 households who used chemicals.

Wang Dehong, who has been farming watermelons for 20 years, couldn’t understand why his fruit also exploded as he had not used any chemicals.

Agricultural experts investigating the incident were unable to offer an explanation.

China has approved the usage of the growth chemical under certain quotas. So far, tests show the chemical is safe, Xinhua reported.

However, as the public is increasingly concerned about food safety, experts say a quality tracking system should be introduced, detailing every stage along the food chain, to inform the public fully, and ensure food safety.