Expert sounds alarm on pesticide overuse

China should prioritize the drafting of national standards on pesticides to reduce the amount of residue that is left on agricultural products and prevent damage to the environment, according to a leading researcher.

Zheng Yongquan, a scientist with the Chinese Academy of Agricultural Sciences' Institute of Plant Protection, said national standards on pesticides, including limits on the maximum amount of residue allowed and application guidelines, are badly needed as the country faces mounting pressure to protect its ecology in rural areas.

Last year, the 54-year-old led a team of experts that received the Second Class Award for National Science and Technology Progress for their research into establishing an efficient and low-risk pesticide usage system.

"The improper usage of pesticides is a matter of grave concern. Chemicals in pesticides leach into the environment, not only wasting resources, but also posing a serious risk to the surrounding ecology," he said.

Spraying inefficiencies in the application of pesticides, which lead to massive amounts of waste, also threaten aquatic life, bees and the following year's crop, Zheng said.

To prevent this and enable the rational use of pesticides among farmers, his team developed a system that can verify how much of the chemicals need to be applied.

The team's test kits, which include color-coded test cards, help farmers determine the quality of their sprays and calculate droplet density.

"Most farmers believe that they have sprayed the appropriate amount when there is runoff from the plant leaves, but this is a misconception," Zheng said. "Our method can help them achieve optimum pesticide deposits in the application process."

Between 2013 and 2015, he said farmers in 28 provincial areas who were using the team's techniques cut their pesticide use by between 30 to 70 percent, which helped them save a combined 10.7 billion yuan ($1.5 billion).

More than 300,000 farmers nationwide have been trained in the use of the system so far, but Zheng wants the authorities to focus more on the efficient application of pesticides, so his team's research can be better disseminated.

He also called for the development of a professional register for pesticide sprayers to ensure that only those who are properly trained work with the chemicals.

In turn, his team will work to expand the category of crops that their method can be used with.

Zheng, a native of Gaozhou in Guangdong province, obtained his bachelor's degree in agriculture at Nanjing Agricultural University, Jiangsu province, in 1984. He received a doctorate from Central China Normal University in 2005.

xuwei@chinadaily.com.cn

(China Daily 01/23/2017 page7)