Farmers in Pailin are using pesticides to help crop yields without understanding the harm they can cause, officials said.

The pesticides are not being used properly, and may be harmful to individuals and the environment, officials said.

Farmers in the border area said they were unclear about the instructions, which are written in Thai, but rely on vendor instructions to help kill weeds and pests.

"These pesticides to kill the weeds and insects and other species are Thai made," said Ie Saroeun, a vendor at Pa Phi market in Pailin. "We don't know how to use them properly. But they told us we have to mix one or two sardine cans to 20 liters of water."

Officials worry that improper pesticide use can be dangerous.

Yong Sam Koma, director of the Cambodian Center for the Study and Development in Agriculture, said pesticides can poison buffalo and cattle in the fields.

In the rainy season, pesticides can flow into rivers and into the lakes, where it can kill the fish and can poison humans over the long term, he said.

Some vendors said they sell more during the reason, though others said they sold pesticide in the dry season as well.

Of Pailin's more than 50,000 residents, about 90 percent are farmers, said Phan Pich, Pailin's director of agriculture.

They grow cassava, sesame, green beans, soy beans, peanuts and red corn, he said.

Some of the farmers don't use many pesticides, because the land is new, Phan Pich said. But at the same time, there some farmers who like to use pesticides to kill the grass and save a lot of time.

"We know this problem in Pailin, and we tried to educate and give training to the people at first," he said. "But the people were not so interested in the health impacts."

Farmer Ty Samaun said he he learned exactly what the impact was on his health.

"I once got poisoning, because I did not protect myself," he said. "It made me exhausted and want to vomit."

Still, farmers say they will continue to use pesticides.

Say Som, a farmer outside of town, said he was looking for a better brand of pesticide, but because he couldn't read the instructions, he has to rely on what the vendors tell him.

"If I kill all the weeds, the corn can grow faster," he said.