In the News
February 24, 2006
Helping Chinese farmers step off the pesticide treadmill
Ten years ago, China had plenty of workers to hand weed their farmland, but with fewer young people choosing farming as a profession, the country is looking for quick chemical fixes to their pest management problems. UC Statewide IPM advisor Anil Shrestha visited China to convince them that integrated pest management is, by far, the better long-term choice.
The International Executive Council, a nonprofit organization sponsored by the U.S. Department of Commerce, was looking for a weed expert to help China with its weed problems. Last November, Shrestha, a weed ecologist, was invited by the organization to travel to Beijing and Feidong County, a county in Anhui province, south China.
"Traditionally, the country has relied on a hand weeding system, but with so little manpower, they have resorted to herbicides for the last decade," says Shrestha. "The country has little access to many herbicides, and, as a result, growers use only two herbicides continuously. They needed help to identify weed species that were escaping the herbicides."
"Entire fields were invaded with Japanese foxtail (Aslopecurus japonicus) and a geranium species," says Shrestha.
Shrestha looked at other areas where Japanese foxtail was being controlled by a grass herbicide. But in this particular location, the herbicide was not controlling foxtail, even when farmers used three to four times more than the recommended rate.
“Although I couldn’t positively determine if the foxtail was resistant to the herbicide without doing a test, it seemed highly likely that it was since Japanese foxtail has developed resistance to this herbicide in other parts of the world. I feel that Chinese farmers need to be reminded that IPM is important, and here was this perfect example of suspected herbicide resistance to show them.”
Shrestha says that big clods on the farmland’s soil surface shielded weed seedlings from the herbicide. Foxtail also seemed to have a long window of emergence, and weed seedlings were emerging after the fields were already treated with herbicide.
“The geranium invasion resulted from a lack of knowledge of what herbicides to use to control them,” says Shrestha. “I suggested some products that could be used, as well as information about how these invasions occurred. One thing that I found striking was that they were very interested in using only chemical control.”
The county extension office there asked Shrestha to give a seminar on ecological weed management. More than 50 extension personnel attended the workshop where he discussed IPM techniques such as better crop rotations, fallowing, (leaving a field without crops for a season or two to get rid of all emerged weeds) varying crop seeding times, and tillage (preparing land for crop planting by plowing or disking).
During the eight days he spent in China, Shrestha gave three lectures on the importance of research-extension linkage, herbicide resistance, and ecological weed management and IPM. Shrestha also visited no-till fields and discussed potential pitfalls of transitioning to no-till systems such as shifts in weed species, initial increase in weed densities, and development of herbicide resistance if a single herbicide is used continuously.
“One goal voiced by every government person I talked with there is a concern for food security,” says Shrestha. “To compete globally and combat their manpower migration to urban areas, they are resorting to pesticides. They want to modernize their farming practices and are looking at ways to enter chemical agriculture. However, they lack the infrastructure that we have here in the U.S. They still need a strong research-extension linkage, and if they are interested in chemical farming, their greatest priority should be on pesticide safety.
“Chinese farmers know about traditional pest control, but this seems to be slowly eroding as they move toward chemical farming,” says Shrestha. “On the other hand, in the U.S., we’re moving toward ecological agriculture and revisiting some of the ecologically sound, traditional practices.”
Shrestha says we should not get too complacent in the U.S. because we practice eco-friendly approaches. “To prevent a global catastrophe, we need to visit underdeveloped countries and help them to create IPM systems that will benefit globally. Many of our food products are imported from China, so it is in our best interest that they produce food in a safe manner there.”
High-resolution image (1.1MB) "UC Statewide IPM Advisor Anil Shrestha shows Chinese government officials how to identify weeds in Feidong County , a county in Anhui province, south China." Photo credit: Courtesy of UC Statewide IPM Program. Photos are for use with this release only. All other uses see Legal Notices.
Stephanie Klunk, Communications Specialist
Anil Shrestha, Weed Ecologist