On September 7, 2023, the General Office of the Chinese Ministry of Agriculture and Rural Affairs issued the ″Letter to seek for opinions on ban of omethoate-included 4 high-toxic pesticides,″ stating that from December 1, 2023, the regulatory authority would revoke registration of omethoate, carbofuran, methomyl and aldicarb formulations, with their production being prohibited. Supplies that have already been legally produced can still be sold and used within their shelf lives, but this will be prohibited as of December 1, 2025, while only technical material produced for export will be maintained under strict supervision.
Since 2009, when the Ministry of Agriculture and Rural Affairs banned the 19 high-toxic pesticides, including carbofuran, the product has gradually been withdrawn from most marketplaces. Although carbofuran is prohibited from application on vegetables, fruit trees, tea trees and Chinese herbal medicines, it has not been banned completely and is deemed as a restricted product, and can still be used as seed coating agent, accounting for a certain market share in some regions.
Currently, the major types of product registrations of carbofuran are seed coating agents and granules, involving a total of 151 registration certificates, of which 100 are related to seed coating agents. The registrations are mainly for application on corn, soybean, millet, cotton and peanut.
Coating agents containing carbofuran
Based on the number and percentage of registrations of carbofuran-containing seed coatings, as well as the sales volumes of manufacturers, it is estimated that the market value of carbofuran-containing seed coatings ranges from between RMB50 million yuan to RMB100 million yuan, which are applied to corn and soybean. Soybean coating use is concentrated in the northeast China while those for corn is mostly for the seed industry.
Insecticidal compound registrations related to corn seed coatings
As shown above, the number of registrations of carbofuran for use in corn seed coatings ranks second only to thiamethoxam, highlighting carbofuran’s considerable influence in the corn seed coating market. In addition to its high toxicity, carbofuran also has the following shortcomings:
-Unstable control effect in specific corn growing regions.
-Long-term storage of coated carbofuran has a certain impact on seed germination rate.
-Coated carbofuran is less attractive than that thiamethoxam and others.
-Carbofuran can cause poisoning to people during the process of coating.
-Carbofuran can be highly toxic to birds and aquatic organisms, being harmful to the environment.
Since carbofuran has many shortcomings, why is it still being used in the seed industry, including for soybean seed dressing?
Firstly, compared with thiamethoxam, carbofuran has an outstanding control effect against soil insects, while the cost of coating is relatively low, with a good cost effectiveness ratio.
Secondly, in northeast China, carbofuran is an important product for control of corn nematodes, including soybean nematodes. Before the registration of thiodicarb as a seed coating agent, controlling corn and soybean nematodes was largely done by carbofuran and carbosulfan, which are regarded as basic necessities for the control of corn and soybean nematodes.
Thirdly, carbofuran is highly toxic to birds, so carbofuran (inclusive of carbosulfan) is recoated as a bird repellent, which are promoted and used in some regions. Therefore, carbofuran has becomes an important bird repellent in China’s northwest spring corn region and southern rice region (carbosulfan).
In 2020, the Ministry of Agriculture and Rural Affairs classified bird repellents as pesticides, making them subject to the provisions of China’s Pesticide Administration Regulation. The promulgation of the regulation has caused bird-repellent products made from natural or biological sources illegal, which are actually less harmful to birds. Instead, carbofuran, carbosulfan and other seed coating products, which are highly toxic to birds, have become compliant products. It is worthy to note that the ban on carbofuran is undoubtedly significant to the ecological environment. At present, it is not registered as a bird repellent pesticide, while the harm caused by birds to agriculture has become an issue in some regions.
Although carbofuran accounts for a certain market share of the corn and soybean seed coating market, the ban will not have a significant impact on the corn seed coating market, as the registrations of thiodicarb and clothianidin for use in corn seed coating make up for the market gap left by carbofuran. For instance, thiodicarb is not only effective in controlling soil insects, but it is also effective in controlling corn nematodes. Nevertheless, since thiodicarb only has a stomach toxicity effect and is not systemic, its effect in controlling soil insects needs more time to be proven, bearing in mind that it would be ineffective in controlling soil insects that are classified as ″soil cutworms.″ In terms of chlorantraniliprole, the price of its technical material has been declining, and it is expected to become a cost-effective seed coating product for controlling soil insects in the future.